School Science Lessons
Please send comments to: J.Elfick@uq.edu.au
35. Geology, Earth Science
Table of Contents
34.5.3.01 Earthquakes, Richter scale
36.3.01 Elements in the Earth's crust, abundance of elements
35.6.0 Geological time scales
35.5.0 Geology fieldwork
35.2.0 Minerals, properties of minerals
35.3.0 Ores and ore bodies
35.4.0 Rocks and minerals, general properties
35.7.0 Rocks, major groups of rocks
35.2.0 Minerals, properties of minerals
A mineral is a naturally occurring inorganic substance obtained by mining,
having distinctive chemical and physical properties.
19.4.21 Mineral salts, food additives
Mineral wool, rock wool, stone wool, mineral
fibres, used for seed germination, insulation, filters
18.104.22.168 Minerals mined at the
Broken Hill mines, Australia
Part 9. Geology, Earth Science (See
Topsie Jewellery, Crystals, minerals, Melbourne) (Commercial)
Actinolite, Ca2(Mg, Fe2+)5(Si8, O22)(OH, F)2
Adamant, traditional term for a very hard rock, especially diamond or
a banded chalcedone, blue agate is light/bright blue
Albite sodium feldspar, Na(AlSi3O8)
Amazonite, microcline, KAlSi3O8, blue-blue/green
22.214.171.124 Amber, C12H20O,
Amber (substance, smell, colour),
35.14.3 Amethyst, SiO2
126.96.36.199 Ammonium chloride (volcanoes), NH4Cl
35.20.3 Amosite amphibole,
35.17.0 Amphibole, common hornblende
Anatase, titanium (IV)
oxide, TiO2, titanium dioxide
35.20.1 Anglesite, lead sulfate, lead vitriol,
Anhydrite, CaSO4, "snake alabaster"
35.20.2 Antimony, Sb, natural antimony
188.8.131.52 Apatite, Ca5[F (PO4)3]
Aragonite, CaCO3, calcium
Argentite, Ag2S, silver glance
184.108.40.206 Arsenic, minerals containing arsenic
35.20.3 Asbestos, hydrous magnesium silicate
220.127.116.11 Aquadag (See 4.)
35.20.4 Azurite, basic copper carbonate, blue
carbonate of copper, 2CuCO3.Cu(OH)2
35.20.5 Bauxite, Al2O3.2H2O
34.9.6 Birth stones
35.20.6 Bornite, Cu5FeS4,
18.104.22.168 Bustamite, calcium manganese
Cadmoselite, CdSe, cadmium (II) selenide
Cadmium sulfide, CdS, greenrockite
35.19.0 Calcite, CaCO3, calc-spar
22.214.171.124 Calcite crystals (Physics)
126.96.36.199 Calomel, Hg2Cl2,
Coal, coal gas, coal tar
188.8.131.52 Carbon, C
35.19.2 Carbonates, CO32-,
35.22.7 Carving stones, Limestone,
35.20.7 Cassiterite, SnO2, tinstone
Celsian, BaAl2Si2O8, barium feldspar
35.20.8 Cerussite, lead carbonate, ceruse, white
lead ore, PbCO3
(II) sulfate, CuSO4.5H2O (mineral)
35.14.4 Chalcedony, SiO2
35.20.11a Chalcocite, Cu2S
35.20.9 Chalcopyrite, CuFeS2
Chrysoberyl, Al2BeO4, alexandrite
184.108.40.206 Cinnabar, HgS, mercuric sulfide
220.127.116.11 Calomel, mercury (I) chloride
35.23.1 Coal, coal tar
35.23.9 Coal seam gas, CSG, CTL
35.20.11 Copper, Cu, natural copper
Coprolites, fossilized animal dung
Cornelian onyx, SiO2
35.20.12 Coronadite, lead manganese oxide, Pb2Mn8O16
18.104.22.168 Corundum, Al2O3
+ (ruby, sapphire
Crocidolite, riebeckite asbestos, tiger's eye,
Crocoite, PbCrO4, red lead ore
35.20.13 Cryolite, sodium aluminium fluoride
Cuprite, Cu2O, red oxides of copper
22.214.171.124 Diamond, C
Diatoms, Diatomaceous earth
35.19.1 Dolomite, CaMg(CO3)2
126.96.36.199 Erinite, Minerals containing arsenic
35.15.0 Feldspars group
35.20.14 Fluorspars, -(AlSi3O8)
Fluorite, fluorspar, calcium fluoride, CaF2)
2.6 Free element metals
188.8.131.52 Fuller's earth
35.20.15 Galena, PbS, lead (II) sulfide, lead
sulfide, lead glance, blue lead
184.108.40.206 Garnet (Mn3, Al2, Si3, O12),
or Mn3Al2[SiO4)3, manganese
aluminium silicate, spessartine, spessartite
35.20.17 Goethite, FeO(OH), hydrated iron oxide, hydrous iron oxide
35.20.18 Gold, Au, natural gold, medical use
Glauberite, brongniartite, Na2SO4, CaSO4
220.127.116.11 Graphite, "lead pencil",
Greenockite, CdS, cadmium sulfide mineral
Greigite, Fe3S4, iron (II, III) sulfide, mineral
35.22.6 Gypsum, CaSO4.2H2O,
calcium sulfate, plaster of Paris
Halite, NaCl, rock salt
clay mineral, Dragonite, in plastics, flame retardants, paints
Hausmannite, manganese (II, III) oxide, Mn3O4,
manganese tetroxide, insoluble in water, soluble in HCl
Hawleyite, CdS, cadmium sulfide mineral
35.20.20 Haematite, Fe2O3
35.17.0 Hornblende (amphibole group)
Hyalite, SiO2.H2O, silicon dioxide, glassy opal,
Hydroxyapatite, Ca5[OH (PO4)3], Ca10(PO4)6(OH)2,
similar to bones, so bioactive and used in surgical implants
Hydrozincite, Zn[(OH)3CO3], zinc bloom
Illite, KAl4(Si, Al)8O20(OH)4,
is the most common clay mineral.
Iron, Fe, in ultra basic rocks, meteorites
35.20.21 Ilmenite, FeTiO3, titanoferrite
Jadeite (in Hornblende)
35.14.0 Jasper, SiO2,
18.104.22.168 Kaolinite, Al4[(OH)8, Si4, O10],
Kerargyrite, AgCl, horn silver
22.214.171.124 Kyanite, Al2(O, SiO4)
Langbeinite, K2Mg2(SO4)3, may be in "potash fertilizers"
35.20.55 Lapis lazuli
35.20.22 Lead, Pb
126.96.36.199a Lead paint
188.8.131.52b Lead tetra-ethyl,
Limonite FeO(OH), Fe2O3.xH2O
Mafic, rich in Mg or Fe, rocks rich in ferromagnesium minerals
Magnesia, magnesium oxide,
MgO, periclase mineral
Magnesia, in Greece
Magnesite, MgCO3, bitter spar
35.20.23 Magnetite, Fe3O4
184.108.40.206 Magnetite, Magnet assortment,
35.20.24 Malachite, Cu(OH)2.CuCO3,
or Cu2[(OH)2, CO3], copper carbonate
35.23.3 Marble, CaCO3
Marbelite (swimming pools)
35.20.25 Marcasite, FeS2
Mascagnite, ammonium sulfate crystals in white
to yellow stalactite-like masses, soft, water soluble, good cleavage
Melanterite, Iron (II)
35.16.0 Mica group
220.127.116.11 Birefringent mica
35.20.27 Millerite, NiS
red oxide of lead, red lead
salt, sodium sulfate, Na2SO4.10H2O, glauberite
35.20.28 Molybdenite, molybdic ochre, MoS2
Molybdite, molybdenum ochre, MoO2
Monazite, reddish phosphate rare mineral (Ce,
La, Nd, Th)(PO4.SiO4)
18.104.22.168 Montmorillonite (smectite)
Moonstone, K[(Si, Al)4O8],
35.20.54 Nacre, mother of pearl
Nahcolite, NaHCO3, thermokalite, sodium hydrogen carbonate
mineral, in evaporates
Natron, Na2CO3.10H2O (+ some NaHCO3
+ NaCl, sodium carbonate decahydrate), in saline lake beds
35.20.29 Nickel, Ni
35.20.30 Nickeline, NiAs, niccolite, arsenical
22.214.171.124 Obsidian, volcanic glass
35.18.0 Olivine group (Mg, Fe)2SiO4
35.14.2 Opals, SiO2.nH2O
126.96.36.199 Opal valuation
188.8.131.52 Orpiment, Minerals containing arsenic
Orthoclase feldspar, KAlSi3O8,
35.21.3 Pegmatite, beryl, topaz,
Periclase, MgO, magnesium oxide
184.108.40.206 Perlite, Obsidian
Perthite, Group 1. Alkaline feldspars
35.23.4 Petroleum, crude oil
35.20.31 Platinum, natural platinum, Pt
35.20.32 Pyrite, FeS2, iron sulfide,
iron disulfide, sulfuric pyrites, iron pyrites, fool's gold
(IV) oxide, mineral, MnO2
35.20.33 Pyromorphite group, Pb5(PO4)3Cl,
35.20.34 Pyrrhotite, FeS, iron sulfide, magnetic
35.14.0 Quartz, SiO2,
silica (rock crystal, rose quartz, smoky quartz, milky quartz, jasper,
tiger's eye, adventurine, bloodstone)
35.23.5 Quartzite, SiO2
220.127.116.11 Realgar, As4S4,
Minerals containing arsenic
35.20.35 Rhodochrosite, MnCO3, manganese
carbonate, manganese spar
35.20.36 Rhodonite, MnSiO3, or ([Mn, Ca]SiO3)
Rock crystal, SiO2
Rose quartz, SiO2
35.20.37 Rutile, TiO2, titanium (IV)
Sagenite, TiO2, mineral
35.20.38 Scheelite, CaWO4, calcium
35.22.6 Selenite, CaSO4.2H2O,
35.21.6 Serpentine, Mg6Si4O10(OH)8,
Siderite, FeCO3, chalybite, spathose iron
35.22.8 Siltstone, mudstone, marl, loess
Silica, SiO2, silica gel, silicon dioxide
Silicates, -(SiO4) (Chemistry)
35.14.1 Silicates (Geology)
Silicic acid, silicon oxyacid, metasilicic acid, H2SiO3
35.14.1 Silicates group, Opals,
35.20.39 Silver, Ag, natural silver
35.23.6 Slate (clay, mudstone,
35.20.40 Smithsonite, ZnCO3 (basic
zinc carbonate, ZnCO3.2ZnO.3H2O), calamine, zinc
igneous, plutonic mineral, changes colour in sunlight, self-adjusting
ZnS, zinc sulfide, zinc blende, mock ore, mock lead, black jack
Spodumene, LiAlSi2O6, lithium aluminium silicate,
forms 6 m crystals, grey-white ash when ignited
35.20.42 Stibnite, Sb2S3,
antimonite, antimony glance, grey antimony
35.20.43 Stilbite, lamellar zeolite, hydrated
sodium calcium aluminium silicate
Strontianite, SrCO3, strontium carbonate
Struvite, [(NH4)MgPO4.6H2O], ammonium
35.20.44 Sulfur, S, natural sulfur
Sulfur, S (Chemistry)
Sunstone, Ca(Al2, Si3, O3)Na(Al, Si3, O8),
potassium chloride (Mineral)
35.23.7 Talc, Mg3Si4O10(OH)2
Tantanite, calcium titanium silicate, source of titanium, jewel stone
Tellurium, natural tellurium, Te
35.20.45 Tin, Sn
Tin, Sn (Chemistry)
Titanite, CaTi(SiO4)O, sphene
35.20.37 Titanium (TiO2, titanium
(IV) oxide, rutile)
Tobermorite, calcium silicatehydrate, Ca5Si6O16(OH)2.4H2O
35.21.3 Topaz, Al2SiO4(OH, F)2,
(in Pegmatites), beryl, zircon
12.1.28 Trona, Na3H(CO3)2.2H2O,
Prepare bath salts with sodium carbonate and with sodium sesquicarbonate
Turquoise, CuAl6[(OH)2, PO4]4.4H2O,
35.20.46 Uraninite, UO2, pitchblende,
35.20.47 Uranium, U, fission
Valentinite, Sb2O3, antimony bloom
18.104.22.168 Vermiculite (Mg, Fe+2, Fe+3)3[(Al, Si)4O10](OH)2, 4H2O
Witherite, Barium carbonate,
35.20.48 Wolframite (Fe, Mn)WO4
Wollastonite, Ca3(Si3, O9), calcium
silicate, table spar, calc-flints
35.20.49 Zeolite (T5O10, T10O20
chains), e.g. tetrapropylammonium (TPA) ZSM-5, clinoptilolite
35.20.50 Zinc, Zn
Zinc blende, ZnS
35.20.51 Zincite, ZnO, red oxide of zinc
Zircon, ZrSiO4, zirconium silicate
Zirconia, ZrO2, zircon-favas
22.214.171.124 Minerals mined
at the Broken Hill mines, Australia
The minerals of Broken Hill are world famous because many of them are
rare and beautiful.
Unfortunately, most of the rare minerals were found in the top sections
of the mine where the sulfide ore minerals had been weathered
and oxidized by groundwater to produce a dazzling array of secondary
These areas of the mine are long worked out and are not producing ore
or mineral specimens.
1. Ore minerals of the primary (sulfide) zone
2. Gangue (waste) minerals of the primary (sulfide) zone
3. Ore minerals of the oxidized zone
Earthquakes are violent moving or shaking of the Earth's caused by geological
forces or volcanic activity.
Seismic waves are the vibrations from earthquakes that travel through
They are recorded on seismographs that record a zig-zag trace of the
amplitudes of ground oscillations.
Seismographs can detect earthquakes from sources anywhere in the world.
The Richter Magnitude Scale (Charles F. Richter, USA, 1935), an open-ended
scale, is used to compare the size of earthquakes
from the logarithm of the amplitude of waves recorded by seismographs,
adjusting for the distance between seismographs and the
epicentre of the earthquakes.
Each point on the scale presents a ten-fold increase in magnitude.
Magnitude is expressed in whole numbers and decimal fractions, e.g.
strong earthquake magnitude 6.3.
The more recent Moment Magnitude Scale, devised for more precise study
of great earthquakes, is a logarithmic scale of 1 to 10 that
enables seismologists to compare the energy released by different earthquakes
on the basis of the area of the geological fault that
ruptured in the earthquake.
34.9.6 Birth stones
January, garnet | February, amethyst | March, bloodstone | April, diamond
| May, emerald | June, pearl |
July, ruby | August, sardonyx | September, sapphire | October, opal
| November, topaz | December, turquoise |.
35.24.0 Make artificial
35.24.1 Make artificial igneous rocks, alum crystals,
35.24.2 Make artificial rocks, sedimentary rocks
35.24.3 Make artificial rocks, metamorphic rocks
35.24 Make igneous rocks, alum crystals, sulfur
Borax mineral, [Na2B4O5(OH)4].8H2O,
Tincal, found at edge of borax lakes.
Borax has a sweet alkaline taste, hydrated sodium borate, di-sodium
tetraborate (III)-10-water, Na2B4O7.10H2O
occurs in evaporite deposits, salt lakes, playas and efflorescence on soils
in arid regions, in solution in some
Ulexite, alkaline taste, NaCaB5O6(OH)6.5H2O,
hydrated sodium calcium borate hydroxide, is found associated with borax
When ulexite is polished and has two smooth sides it has the fibre optic
property of projecting an image through internal reflection from
the bottom of the to the top, so some people call it "TV stone"!
The fibres have the formula B5O6(OH)6.
Feldspars group, "field stone", -(AlSi3O8)
Feldspars occur as aluminosilicates of alkali metals and alkaline earths,
have pink colour but red-green or yellow colour if impure and
some are white, e.g. sodium feldspar or albite, Mohs scale of hardness
6, white streak, glassy lustre, good cleavage in two directions,
conchoidal fracture, specific gravity 2.55-2.76.
It is the most common rock forming silicate in igneous rocks and some
Feldspars are used in the interior of buildings as an ornamental veneer.
Feldspars have dull surfaces unless light strikes at just the right
Feldspars in rocks may cause flashes of light because of reflection
from two directions of cleavage at right angles to each other.
Feldspars are used in glazes and the manufacture of glass, enamels,
polishes, and roofing material.
Feldspars are divided into two groups:
Group 1. Alkaline feldspars (K, Na)AlSi3O8, include
orthoclase feldspar, microcline (KAlSi3O8), and sanidine,
potassium and less or no sodium, calcium may substitute for potassium
and sodium, monoclinic or triclinic crystal system, crystals
prismatic to tabular (also as irregular grains or cleavable masses),
vitreous to silky lustre, colourless, white or pink (also green),
white streak, Mohs scale of hardness 6, two perfect cleavages at close
to 90o, cleaves rather than fractures, not ferromagnetic, does
not react with hydrochloric acid.
Sanidine and orthoclase feldspar are the high temperature alkali feldspars,
occur in alkali-rich igneous rocks, e.g. rhyolites and granites.
Microcline, the lower temperature alkali feldspar variety, occurs in
granites, pegmatite dikes and hydrothermal vein deposits.
Orthoclase feldspar and microcline also occur in some metamorphic rocks
and as discrete grains in immature sandstone.
Minor colourless or white plagioclase intergrown with pink microcline
is called perthite.
Group 2. Plagioclase feldspars
Plagioclase feldspars, NaAlSi3O8, CaAl2Si2O8,
include albite, anorthite, and andesine contain less or no potassium,
crystal system, tabular crystals (also as irregular grains or cleavable
masses), vitreous to silky lustre, white to grey colour (also blue
to green), white streak, Mohs scale of hardness 6, two perfect cleavages
at close to 90o, cleaves rather than fractures, not
ferromagnetic, does not react with hydrochloric acid, occurs mainly
in mafic and intermediate igneous rocks, e.g. basalt, andesite.
Note the pink colour and cleavage, then turn the specimen in the light
and note flashing surfaces.
To distinguish the two groups, the alkali feldspars all have the perthite
structure and plagioclase feldspars have lamellar twinning.
Note the fine lines on a cleavage surface of plagioclase feldspar but
not on orthoclase feldspar.
Feldspars include the following:
1. Potassium feldspar, orthoclase feldspar, KAlSi3O8
Brown to colourless, vitreous pearly lustre, translucent to transparent,
Mohs scale of hardness 6-6.5, specific gravity 2.55, good
cleavage, brittle uneven fracture, massive granular crystals, monoclinic
system, main constituent of many different rocks
2. Sodium feldspar, albite, NaAlSi2O8
3. Calcium feldspar, anorthite, CaAl2Si2O8
4. Barium feldspar, celsian, BaAl2Si2O8
5. Moonstones, K(SiAl)4O8,
feldspar, gemstone have blue-white spots with a silvery colour like moonlight.
Moonstone is silvery-white, or milky white with a soft blue shimmer moving across its face as the stone is moved, called "adularescence".
The distinctive shimmer, caused by tiny albite inclusions, reflect and
scatter light, mimicking the moon's glow, hence the gem's name.
6. Sunstones, Ca(Al2Si3O3)Na(AlSi3O8),
35.16.0 Mica group
See: Mica (Physics and chemistry)
See diagram 126.96.36.199: Colours in mica (University
The group has dark brown colour (biotite mica, Jean-Baptiste Biot,
1774-1863) or is colourless (muscovite mica), Mohs scale of
hardness 2.5-3, white streak, pearly to glassy lustre, single perfect
cleavage and specific gravity 2.7, forms soft shiny flat flakes.
Muscovite mica or white mica, K2Al4Si6Al2O20(OH, F)4
contains no iron, so is clear and colourless.
Biotite mica, K2(Mg, Fe)6-4(Fe, Al, Ti)0-2(Si6-5Al2-3O20)(OH, F)4,
is brown to black, and seen in granite as dark glittering specks.
Mica can be split into very thin elastic sheets that can be split into
thin transparent layers.
On split faces the lustre is bright and pearly white but other faces
are dull and rough.
Formerly, it was used in place of glass in beehives and in foundries,
but now is used as a heat resistant material in windows, stoves, eye
shields, and sparkling makeup.
Mica is a poor conductor of electricity so it is used in electrical
The mica is used as a filler in plasterboard and paint, as a surface
coating on welding rods, a release agent for coating foundry moulds,
and as spray-on decorative glitter.
Crush the specimen and note the sparkling surfaces.
Hornblende, NaCa2(Mg, Fe2+, Fe3+, Al5(Si,
Hornblende, in the amphibole group, has dark green to black colour,
Mohs scale of hardness 5 to 6, brown to grey streak, glassy to
dull lustre, two imperfect cleavages, uneven fracture, and specific
It forms small dark green to black crystals and is seen with biotite
mica as dark patches in granite.
Actinolite is a similar mineral, Ca2(Mg, Fe2+)5(Si8, O22)(OH, F)2,
that includes nephrite or nephrite jade, the jade popular in China.
Nephrite jade, Ca2(Mg, Fe)5(Si8, O22)(OH, F)2
is a fine grained massive variety of actinolite that is used for ornaments
Jadeite, is the other jade, Na(Al, Fe)SiO6, NaAl(Si2, O6),
pyroxene group, from Myanmar (Burma).
Note the hexagonal cross-section of crystals, cleavage and colour of
the hornblende specimen.
35.18.0 Olivine group
Olivine group (Mg, Fe)2SiO4, peridote, chrysolite
The olivine group has emerald-green to green-yellow colour, Mohs scale
of hardness 6.5-7, white streak, glassy lustre, poor
cleavage, conchoidal fracture, and specific gravity 3.2-3.4.
It weathers easily to leave the rock brown because of iron oxide stain.
It occurs as sugary crystals that sparkle like quartz in basalt rocks.
Quartz and olivine seldom occur together in igneous rock.
Olivine occurs in the darkest rocks deficient in silicon.
It forms gemstone crystals, e.g. chrysolite, that are transparent and
have a glassy lustre.
Volcanic "bombs" may have a lining of olivine crystals in the inner
Note the colour, hardness and density of the specimen.
Calcite, CaCO3, calc-spar, Iceland spar
3.54.8 Prepare stalactite crystals
Calcite has white colour, in cracks in sedimentary limestone, Mohs scale
of hardness 3, white streak, glassy lustre, good cleavage in
three directions (not at right angles), causing rhombohedral shape,
conchoidal fracture, specific gravity 2.7 and greasy to touch.
Calcite occurs in four-sided crystals and as chalk and limestone.
It forms from evaporation of sea water and occurs in sedimentary and
metamorphic rocks, but not in igneous rocks.
The crystallized varieties always break into little four-sided pieces
when hit with a hammer.
Iceland Spar is a clear crystal with refractive index 1.49 and 1.66
causing a double refraction effect, birefringence, double image caused
by light polarization, used in the Nicol prism and in bomb-sights.
Sea animals use calcite to build a shell or outer skeleton.
Some types of calcite are used for building blocks, for making lime
and in the glass and steel industries.
Weathering of pyrite liberates sulfuric acid that may change calcite
into gypsum and other sulfates.
In limestone caves, calcite occurs as stalactites hanging from the roofs
of limestone caves and stalagmites that grow up from the floor.
Ca(HCO3)2 (aq) --> CaCO3 (s) + H2O,
(l) + CO2 (g)
Note effervescence with cold dilute hydrochloric acid, hardness and
Turn the specimen in the light and note flashing surfaces.
If the specimen is a clear crystal, place it on a line and observe the
refracted double line.
Dolomite, Ca(CO3)Mg(CO3), [Mg, Ca (CO3)2],
(+ some silica), magnesium calcium carbonate
Dolomite has colour white to pink, Mohs scale of hardness 3.5-4, glassy
to pearly to dull lustre, white streak, good cleavage in three
directions and specific gravity 2.84.
The term "dolomite" is a general term for rocks with a high ratio of
magnesium to calcium carbonate.
Dolomite is used as sources of magnesium and in lining furnaces, fertilizers,
ceramics, mineral wool, welding fluxes.
The medical use is to supplement calcium and magnesium deficiency.
Note the colour, hardness, density, lustre, and slow reaction to dilute
Carbonates, CO32-, mineral carbonates
1. Azurite, 2CuCO3.Cu(OH)2: 35.20.4
2. Calcite, CaCO3: 35.19.0
3. Dolomite, CaMg(CO3)2: 35.19.1
4. Magnesite, MgCO3
5. Siderite FeCO3, chalybite, spathose iron
6. Smithsonite, ZnCO3: 35.20.40
7. Witherite, barium carbonate, BaCO3
8. Malachite CuCO3Cu(OH)2: 35.20.24
Calcite, dolomite and siderite are the main components of limestone.
Anglesite, lead sulfate, PbSO4
Anglesite has non-metallic lustre but is adamantine when crystalline
and dull earthy, Mohs scale of hardness 3, specific gravity 6.3 and
is colourless, white, grey, pale yellow, transparent green, transparent
to translucent colourless.
It may occur as groups of striated, blocky rhombs and flattened, simple,
to complex prisms.
Anglesite, lead sulfate, PbSO4, is another widespread secondary
mineral from the oxidized zones of the Broken Hill mine.
It is found in vughs (irregular voids) and fractures in all mines in
the outcrop area.
The associated minerals are marshite, iodargyrite, pyromorphite, stalactitic
goethite, and goethite matrix replaced by cerussite.
35.20.2 Antimony, Sb
See: Antimony, Sb (Chemistry)
Antimony occurs rarely as the metal, but in hydrothermal veins combined
with other elements, e.g. sulfur.
188.8.131.52 Arsenic, minerals
Arsenic, natural arsenic, As
Arsenic trisulfide, As2S3, orpiment, yellow pigment
Arsenopyrite, mispickel, arsenical pyrites, FeAsS
Anorthite, calcium feldspar, CaAl2Si2O8
Erinite, Cu5(OH)4(As, O4)2,
emerald-green, basic copper arsenate crystal, name from "Ireland"
Nickeline, niccolite, arsenical nickel, NiA: 35.20.30
Orpiment, tinsel, deep yellow colour ("gold-pimented"), As2S3
Realgar, As4S4, arsenic sulfide, ruby sulfur,
ruby of arsenic, non-metallic lustre,
poisonous, red paint pigment, pesticide, "orpiment", highly toxic orange
Asbestos is a group of fibrous silicate minerals, compact and hard,
sometimes resembling petrified root of a tree, so was called
"mountain flax" or "salamander's wool".
The word is derived from the Greek meaning "incombustible".
The colours range from brown to yellow to green.
It usually occurs mixed with serpentine rock or mica schist.
Tiger's Eye and Hawk's Eye, used for men's cufflinks, are altered varieties
of asbestos with wavy bands of light that glow and ripple as
you move them.
Asbestos is a fireproof substance and formerly was widely used as a
heat insulator, for packing and for fireproof garments and fabrics.
The main asbestos mineral is white asbestos or chrysotile, hydrous magnesium
silicate, Mg3Si2O5(OH)4, in
serpentine mineral group.
Blue asbestos, crocidolite, is the most lethal to humans.
Brown asbestos is amosite.
Inhalation of the short asbestos fibres can cause the lung disorder
asbestosis, mesothelioma lung cancer and bronchiogenic cancer.
The manufacture and use of white chrysotile asbestos products, banned
in Australia in 2003, and since banned in many countries.
Do not cut old "fibro" sheets or pieces of asbestos, but replace the
whole sheets with non-asbestos sheets.
The government may give advice on whether asbestos is present in buildings
and how to get rid of it.
Asbestos is extremely toxic if inhaled into the lungs and causes two
cancers, bronchiogenic carcinoma and mesothelioma.
It is safe to touch, but do not inhale the fibres.
Other forms of asbestos (amosite, anthophyllite, tremolite, actinolite
and chrysotile) are not as dangerous by inhalation as crocidolite,
but should be treated similarly.
Specimens of ash should be stored in a sealed container until collection
by a licensed waste contractor.
Correctly embedded asbestos, such as that found in geology teaching
sample sets, does not pose a threat to health provided that the
embedding material remains intact.
In Queensland, Australia, asbestos samples sealed in plastic bags were
available in school minerals sets, but some boys broke open the
plastic bags and handled the asbestos samples.
So the Queensland government was forced to take out the asbestos samples
from the school mineral sets.
1.0 Blue asbestos
1.1 Crocidolite, Na2Fe3Fe2[(OH, F)Si4O11]2,
riebeckite, asbestos, tiger's eye, cat's eye, blue asbestos, amphibole,
is the most lethal
Crocidolite asbestos and blue asbestos is Not permitted in schools.
Store demonstration specimens in sealed containers or embedded in plastic.
2.0 Brown asbestos (amosite, mysorite)
2.1 Amosite, amphibole (Mg, Fe)7(OH, Si4O11)2
3.0 White asbestos
3.1 Actinolite, amphibole, Ca2(Mg, Fe2+)5(Si8, O22)(OH, F)2,
green-grey crystals, powdered mineral herbal medicine
3.2 Anthophyllite asbestos, amphibole (Mg, Fe)7(OH, Si4, O11)2
3.3 Chrysotile, Mg3Si2O5(OH)4,
the main asbestos mineral, white asbestos, hydrous magnesium silicate,
in serpentine mineral group
3.4 Tremolite, amphibole, Ca2Mg5(OH, F)2(Si4, O11)2
3.5 Byssolite, amphibole, Ca2Mg5(OH3F)2(Si4, O11)2.
Augite (monoclinic, pyroxene, silicate), [(Ca, Mg, Fe2, Fe3, Ti, Al)2][(Si, Al)2O6]
Augite, Crystal systems, crystal habit, crystal form: 35.8 (See 4. Monoclinic)
Augite, Silicates group, polysilicates, polysilicon: 35.14.1 (See 3. Pyroxenes, MgSiO3,
e.g. augite, jadeite, diopside).
Meerschaum is found as floating white lumps and was formerly used for
tobacco pipes and holders.
It is a soft, light-coloured, hydrated magnesium silicate found in Asian
If newly dug up, it lathers like soap and has been used as soap.
Epsomite, hydrated Epsom salts, magnesium sulfate, bitter salt (kieserite),
MgSO4.7H2O, constipation medicine.
Azurite, 2CuCO3.Cu(OH)2, basic copper carbonate
Azurite has non-metallic vitreous lustre, Mohs scale of hardness 3.5-4,
specific gravity 3.83, intense medium to dark azure blue colour,
transparent to translucent, colourless streak.
Azurite (copper carbonate) has a habit consisting of short tabular
prisms, equidimensional plates, long spear-like crystals with
The associated mineral is malachite, Cu2[(OH)2, CO3].
Aluminium oxide, Al2O3,
Bauxite, Al2O3. x2H2O, hydrated aluminium
oxide, is a residual sedimentary mineral that contains alumina and other
oxides of aluminium
in the amorphous or crystalline state.
So it is more a rock-like mixture than a mineral.
Bauxite is a mixture of iron and aluminium hydroxides and oxides.
It is usually formed by weathering in tropical regions.
It is the most important ore for production of aluminium.
Bauxite has non-metallic lustre, white streak, no good cleavage, can
be scratched by the finger nail, white to brown grey colour,
uneven fracture, specific gravity 2.0-2.5.
Bornite, bournonite, Cu5FeS4
Bornite has purple to silver grey to black colour, Mohs scale of hardness
2.5-3, metallic lustre, black streak, poor cleavage, uneven
to conchoidal fracture, and specific gravity 5.09
It resembles gold or iron pyrite, but is more brittle than gold.
Bornite is called "cog wheel ore", because twinned crystals form in that
Bornite may be a mixture of copper sulfides including Cu2S,
(chalcocite) and CuS (covelite).
Note the twinning habit colour and density of the specimen.
Cassiterite, tinstone, SnO2
Cassiterite has white to grey to black colour, with fractured pieces
having brown colour, Mohs scale of hardness 1.5-2, white to grey
streak, metallic lustre with the crystal faces often brilliantly shiny,
cleavage poor, specific gravity 6.6 -7.15.
It is quite brittle, usually occurs in ancient granite rocks, e.g. pegmatite,
as small veins crossing the granite, and forms twin crystals.
Note the density, colour and hardness of the specimen.
Cerussite, lead carbonate, PbCO3, ceruse, white lead ore
Cerussite has a non-metallic and adamantine lustre, Mohs scale of hardness
3-3.5, specific gravity 6.55, is colourless or white or grey,
transparent to subtranslucent, but may be opaque white to wine yellow
to brown-yellow to smoky brown, colourless streak.
It occurs as ore grade concentrations as a secondary mineral from the
oxidized zones at Broken Hill where most of it is opaque white.
However, wine yellow, yellow brown, smoky brown, transparent and translucent
It occurs as reticulated masses, complex arrowheads twinned crystals,
and "jack straw" masses of tubular-shaped crystals.
It is found in ore bodies and is one of the most abundant minerals of
the oxidized zone.
The associated minerals are malachite, [Cu2[(OH)2CO3],
azurite, and bromian chlorargyrite.
Chalcopyrite, CuFeS2, copper pyrite, copper iron sulfide,
CuFeS2, has brassy yellow to green colour but often tarnishes
bronze or iridescent to
form peacock ore, Mohs scale of hardness 3.5-4, dark green to black
streak, metallic lustre, brittle, poor cleavage, conchoidal
fracture and specific gravity 4.1-4.3, brittle and antiferromagnetic.
It is the main copper ore and is also a "fool's gold".
Copper pyrite resembles gold or pyrite, but it has a deeper brass colour
and pyrite has Mohs scale of hardness 6-6.5.
Pyrite is more brittle than gold and weathers to form the secondary
minerals limonite, malachite and azurite.
Chalcopyrite, copper iron sulfide, occurs in veins in garnet, quartzite
and garnet sandstone in ore bodies.
The associated minerals are argentiferous galena and arsenopyrite, FeAsS.
It may become magnetic when heated.
Note the crystal habit and softness of the specimen.
Cinnabar, HgS, mercuric sulfide, cinnabarite, quicksilver, HgS, mercuric
sulfide (II) sulfide (calomel found with cinnabar), red crystals, native
China red, vermilion, is used for Chinese chops, and was used in old
paintings but is no longer used .
Cinnabar has brick red to scarlet colour, Mohs scale of hardness 2-2.5,
red to scarlet streak, diamond-like lustre, but sometimes
darker non-metallic lustre, uneven fracture, specific gravity 8.19.
It is the most important mercury ore and is linked with volcanic activity,
Calomel, mercury (I) chloride, is a similar mineral.
Note the density, cleavage and colour of the specimen.
Calomel, mercury (I) chloride, Hg2Cl2, mercury
(I) chloride, mercurous chloride, horn quicksilver, horn mercury, similar
to cinnabar and found with it.
Note the density, cleavage and colour of the specimen.
Copper, Cu, natural copper
See: Copper (Chemistry)
See: Copper compounds,
Copper has copper colour that tarnishes to green, copper red on a fresh
surface but usually dark because of dark tarnish, metallic lustre,
no cleavage, jagged fracture, copper red shiny streak, Mohs scale
of hardness 2.5-3 and specific gravity 8.96.
The rare native copper, Cu, occurs as rounded branches often with green
or blue spots.
Nowadays it occurs in mainly sulfide ores in veins or on the surface
of crevices in sandstone, slates and igneous rocks.
Pure copper is malleable, ductile and can be cut into slices.
It has high thermal and electrical conductivity and resistance to corrosion
so it is an excellent electrical conductor.
Copper combines with zinc to form brass and combines with tin to form
The name copper comes from the island of Cyprus. Copper, Cu, natural
copper, has arborescent forms in large cavities, four-sided
prisms, elongate octahedrons with repeated branches.
Also, stalactitic or dendritic masses in wire-like groups and nail head
Associated minerals are cuprite, Cu2O, red oxide of copper,
and malachite, [Cu2[(OH)2, CO3] in weathering
zone of copper deposits.
Note the colour, crystal form and ductility of a native copper specimen.
Chalcocite, Cu2S, copper (II) sulfide, copper glance mineral,
grey-black-blue, possibly iridescent, dark grey streak, Mohs scale of
hardness 2.5-3, may be formed from other minerals, e.g. bornite, crystals
almost hexagonal, igneous or metamorphic in copper deposits.
Coronadite (lead manganese oxide, formerly called psilomelane), occurs
as massive, stalactitic, shawls, cellular, botryoidal habit,
sub-metallic glossy to earthy lustre, Mohs scale of hardness 5-6, S.G.
5.53, colour black to brown black, streak brown black.
Coronadite (lead manganese oxide) originally referred to as psilomelane,
is massive, stalactitic, shawls, cellular, botryoidal habit.
Abundant in the upper levels of the oxidized zone and outcrop with associated
mineral goethite forms the matrix for secondary minerals.
Corundum, Al2O3 + chromium, iron, titanium,
(Mohs scale of hardness 9, ruby, sapphire)
Aluminium oxide, Al2O3,
Corundum as ruby contains Cr and is always red.
Sapphire contains Fe and Ti and is always blue-green, so a ruby is sometimes
called a "red sapphire".
Cryolite, sodium aluminium fluoride, Na3AlF6
Cryolite has colourless to white to yellow colour, and sometimes
purple to black colour, Mohs scale of hardness 2.5-3, white streak,
greasy to glassy lustre, no cleavage, uneven fracture and specific gravity
The refractive index is 1.34 so the specimen almost disappears in water.
Colourless rare mineral used as a flux in electrolytic production of
aluminium from bauxite, and is manufactured synthetically.
Note the disappearance in water, no salty taste and density of the specimen.
Emery is the naturally occurring mixture of the mineral corundum, magnetite
and others, is very hard and is used as an abrasive both as
powder or as blocks or wheels.
Fluorspar, CaF2 (fluorite, calcium fluoride, blue john, Derbyshire
spar), has many colours, colourless if pure but usually purple or green
yellow, depending on dissolved impurities, Mohs scale of hardness 4,
white streak, glassy lustre, good cleavage in four directions,
specific gravity 3.0-3.3.
Coloured specimens may fluoresce in ultraviolet light or glow when heated.
It occurs in veins in igneous rocks and can form twin crystals.
Large crystals have been carved into small vases.
It is used as a flux to smelt metals and to produce fluorine.
The name comes from the Latin "fluo", meaning "to flow" because it melts
at a low temperature.
Note colour, hardness, cleavage and possible fluorescence of the specimen.
Galena, PbS, lead glance, blue lead, silver grey to black colour, Mohs
scale of hardness 2.5, lead grey streak, metallic lustre, good cleavage
directions, and specific gravity 7.2-7.635.
It can mark paper and when hit with a hammer, breaks into perfectly
cubic pieces because of its cubic cleavage.
Tetraethyl lead [lead (IV) tetraethyl] was formerly used as an "anti-knock"
agent in petrol (gasoline), but not now, because lead is toxic.
Lead is used in X-ray shields, lead cell accumulators, ammunition, fishing
sinkers, solder and type metal.
Galena is the most important lead ore and is the main lead ore mineral
at Broken Hill, Australia.
The silvery metallic lustre and cubic appearance characterize galena,
density of 7.5.
Galena is also the source of much of the silver at Broken Hill, Australia,
because silver atoms can substitute for lead atoms or be present
within minerals such as acanthite (Ag2S) that have formed
within the galena.
Note the density, and cleavage in the specimen.
Goethite, FeO(OH), hydrous iron oxide, needle iron ore, acicular iron
ore, has adamantine to dull lustre, but silky in some fine, or scaly, or
varieties, Mohs scale of hardness: 5-5.5, specific gravity 3.3-4.3,
brown-yellow to dark brown colour, brown-yellow streak.
Limonite (brown iron ore, brown haematite, brown ironstone, is a cryptocrystalline
mixture of mainly goethite, a weathering product
of all iron deposits and in hydrothermal veins, with associated mineral
It has a habit consisting of botryoidal, mamillary, stalactitic masses
and crusts, and it is abundant in the gossanous capping of ore bodies.
35.20.18 Gold, Au
See: Gold (Chemistry)
Gold, E 175, has copper yellow colour like butter, Mohs scale of hardness
2.5-3, gold to yellow streak, metallic lustre, no cleavage,
jagged fracture, and specific gravity 19.3, is malleable, ductile and
can be cut into slices.
Gold is a widely distributed metal and always occurs in a metallic state,
generally as an alloy with silver, copper or iron.
It occurs in thin irregular hydrothermal veins in a quartz reef, placer
deposits and conglomerates.
Gold does not tarnish, so it has been used as the universal standard
Specks of gold can be separated by "panning" so that the greater weight
of the gold causes it to settle, leaving the gravel at the surface.
The "white gold" used in jewellery and decorating pottery is usually
an alloy of gold and nickel, but used in dentistry it is an alloy of gold
3.2.2 Carat (Gold)
Pure gold is rated at 24 carats, so 18 carat gold contains six parts
of an alloy.
Gold leaf, 23-24 carat, is gold beaten into very thin sheets for gilding
decoration and electrical contacts, e.g. gold leaf electroscope.
The concentration of gold in sea water is about 10-30 g / km2,
but no commercial method of extraction is known.
The red-purple alloy guanin, prized by pre-Columbian Indians in the
Cuba region, was an alloy of gold, silver and copper.
Note the colour, and density of the specimen.
Halite, rock salt, NaCl
See: Sodium chloride,
Halite has colourless or white colour, Mohs scale of hardness 2, white
streak, glassy lustre, good cleavage to break into cubes,
conchoidal fracture, specific gravity 2.1-2.6.
The cubic crystals may have an indentation in one surface.
It forms from evaporation of sea water.
It may rise from deep layers to form massive salt domes and act as an
Halite has a characteristic sharp taste.
The inland salt trade was once important for many places, e.g. Salzburg.
Table salt is always snowy white but natural salt has many different
colours because of impurities.
A red colour is caused by ferric oxide (iron oxide), grey is caused
by clay, and brown is caused by plant matter.
Used as table salt, road salt and glass manufacture.
In the Bible, Matthew 5: 13, "Ye are the salt of the earth: but if the
salt have lost his savour, wherewith shall it be salted? It is
thenceforth good for nothing, but to be cast out, and to be trodden
under foot of men."
Although pure sodium chloride cannot lose its saltiness, the rock salt
used in biblical times often contained impurities.
If the sodium chloride content was leached away or lost by evaporation
in very hot countries, the "salt" could indeed lose its salty taste.
Also, fine grain salt may taste saltier than coarse grain salt due to
the greater surface to volume ratio so that more salt dissolve in the
saliva and reach the taste receptors on the tongue.
The evaporates from sea water salt pans are not pure sodium chloride
because they may contain over 10% magnesium chloride to act
as a desiccating agent and assist food preservation.
Note the cleavage at right angles and the taste of salt in the specimen
Haematite, Fe2O3, hematite, iron glance, specularite, antiferromagnetic.
Iron (III) oxide, Fe2O3,
Haematite has grey to black and red to brown colour, Mohs scale of hardness
5-6, red to brown streak, metallic to dull lustre, no
cleavage, uneven fracture, specific gravity 5.26.
It is weakly magnetic.
The crystalline form is black and shiny.
It is an important iron ore and is used in paints as a pigment and in
jeweller's rouge polish.
Haematite is antiferromagnetic, because the Fe crystallizes in a structure
with oxygen ions, in an hexagonal close-packed framework in
a plane, but it is antiferromagnetically coupled between the planes.
Antiferromagnetism occurs when the A and B sublattice moments are exactly
equal but opposite, so the net magnetic moment is zero.
Note the red to brown streak and hardness of the specimen.
Ilmenite, FeTiO3, has black colour and gives a black powder
as in "black sands", Mohs scale of hardness 5-6, brown to black streak,
lustre, no cleavage, conchoidal to uneven fracture, specific gravity
Ilmenite is slightly magnetic.
The particles have been weathered from basic igneous rocks.
Note the density, lustre and streak of the specimen.
Kaolinite, Al2(OH)4(Si2, O5),
Kaolinite, known as white clay, pipe clay, ball clay and China clay,
is used for making pottery.
Kaolinite, commonly potassium alum, is a combination of potassium and
It is a weathering product of feldspars, known as white clay, pipe clay,
ball clay, Cornish clay and China clay, kaolin (also dickite
and nacrite minerals) is used in the manufacture of fine porcelain that
is almost pure kaolin.
The cheaper grades are made with the addition of feldspar.
It is a soft white powder, insoluble in water, dilute acids or alkalis.
Kaolin clay contains mainly kaolinite and some illite.
Kaolin is ingredient of anti diarrhoea medicines to absorb bacteria
and increase the bulk of faeces.
It is very astringent and is used for purifying water.
Soda alum or chrome alum are similar combinations where the potassium
has been replaced by the corresponding metals.
Kyanite, Al2(O, SiO4), disthene, munkrudite, cyanite,
rhaeticite (white grey kyanite) (Greek: kyanos, blue), is an aluminosilicate
Mohs scale of hardness 4-5 and 6.5-7 depending on the direction of the
cleavage planes, colourless streak, vitreous lustre.
Found in aluminium-rich metamorphic pegmatites and sedimentary rock.
Used in refractory and ceramic products, electrical insulators, abrasives,
Elongated, columnar crystals.
Anisotropic, i.e. two different harnesses on perpendicular axes.
35.20.22 Lead, Pb
See: Lead (Chemistry)
Lead rarely occurs as the metal.
It has a metallic lustre, a dark grey colour and high specific gravity
Lead, Pb, occurs mainly as the lead ore galena (lead sulfide, PbS).
It is characterized by a metallic silver lustre and cubic fracture.
Cerussite (lead carbonate, PbCO3) and anglesite (lead sulfate,
PbSO4) are found in areas where galena has been weathered or
exposed to oxidizing groundwater.
Typically this occurred at or near the surface.
Lead was used in water pipes, roofing and pigments, but is now mostly
used in batteries for vehicles and other equipment.
Magnetite, Fe3O4, iron (II, III) oxide (FeO.Fe2O3),
Magnetite nanoparticles, Ferrofluid (Commercial)
Iron oxide (black iron oxide), is a mixed base, Fe3O4
Magnetite (iron (II) diiron (III) oxide, magnetitum, ferrosoferric
oxide, loadstone, triiron tetroxide, black magnetic iron oxide,
ferrimagnetic magnetic lodestone, iron ore, black iron ore, black colour,
Mohs scale of hardness 5.5 to 6.5, black streak, black powder,
metallic to dull lustre, no cleavage, conchoidal fracture, cube-shaped
crystals, specific gravity 5.17.
It is called magnetic iron ore and has magnetic properties unlike any
Formerly, it was the strongest magnet known when known as lodestone,
which acts as a magnet when freely suspended, from
Magnesia, in Greece, but magnetite is no longer
used as a magnet because much stronger and shaped magnets are needed.
It was probably first discovered in China where they used it for the
first magnetic compasses.
Fragments of magnetite will be attracted to a magnet or will affect
a suspended magnetic needle.
Magnetite has about 73% iron but it may also contain magnesium, chromium
Magnetite is widely distributed in igneous rocks and volcanic ashes
so it is an important iron ore used in smelting.
Magnetite is a folk medicine for liver function and a sedative.
Magnetite is ferrimagnetic, not ferromagnetic, because it contains two
magnetic sublattices, A and B, caused by the Fe ion surrounded
by four oxygens and the Fe ion surrounded by six oxygens with uneven,
antiparallel spins on the sublattices, [Fe3+] sublattice A
[Fe3+, Fe2+] sublattice BO4, to result
in a net magnetic moment.
Some bacteria and the brains of bees and pigeons contain tiny magnetite
crystals with perhaps a magnetic orientation function.
Note the magnetic property of the specimen and the streak.
Malachite, copper (II) carbonate
See: Copper (II) carbonate,
Malachite, Cu2(OH)2CO3, or CuCO3.Cu(OH)2,
has a non-metallic lustre, adamantine to vitreous in crystals that are
often silky in
fibrous varieties, dull lustre in earthy types, Mohs scale of hardness:
3.5 to 4, specific gravity 4.03, bright green and translucent
or chalk-green to lush-green colour, pale green streak.
Malachite, copper carbonate, [Cu2[(OH)2CO3],
has botryoidal and sometimes velvety habit.
It is found in ore bodies as powdery to compact fibrous crusts and hemispherical
The associated minerals are azurite and cerussite.
Marcasite, iron sulfide, FeS2, spear pyrites
Marcasite has brass to yellow colour with a green tinge, Mohs scale
of hardness 6.5, green to black streak, metallic lustre, poor
cleavage, uneven fracture, and specific gravity 4.88.
So it is similar to pyrite but has radiating groups of twin crystals
like a cock's comb.
Old specimens may oxidize to give off sulfur in an exothermic reaction.
Note the crystal habit of the specimen and compare the specimen with
An old specimen may have a sulfur smell.
35.20.26 Mercury, Hg
See: Mercury (Chemistry)
Mercury, Hg, is a bright silvery coloured liquid that forms spherical
droplets if spilt.
The relative specific gravity is 13.6.
Mercury was formerly called quicksilver and is the only metal that is
liquid at room temperatures.
It rarely occurs free in rock cavities.
Mercury is used in thermometers, barometers, dental amalgams, silver-plating
of mirrors and to separate gold from silver.
Note the appearance and movement of mercury in a mercury thermometer.
Do not allow students to touch mercury or to have any access to free
surface metallic mercury.
Millerite, NiS, nickel sulfide, hair pyrites
Millerite has brass to yellow colour, Mohs scale of hardness 3 to 3.5,
green to black streak, metallic lustre, cleavage in 3 directions,
but not obvious in thin crystals, and specific gravity 5.3-5.5.
It forms thin, needle-like crystals called "hair nickel" with a bright
It occurs in iron-nickel meteorites.
Note the crystal habit, colour and lustre of the specimen.
Molybdenite, MoS2, has silvery grey to black metallic colour
with a blue tinge, powder has the same colour as the crystal, Mohs scale
hardness 1-1.5, blue to grey streak, can mark paper, good platy cleavage
that forms flakes and specific gravity 5.0.
Molybdenum, Mo, occurs as branches in pipes of quartz but is one of the
less common metallic elements.
The main use of this metal is in making blue pigment in glasses.
Because molybdenite resists repeated shocks, it is added to steel to
improve its strength and toughness.
Note the greasy feel, the marks left on the fingers, and the blue streak
of the specimen.
35.20.29 Nickel, Ni
See: Nickel (Chemistry)
Nickel is blue to white colour, Mohs scale of hardness 3.5, grey metallic
streak, metallic lustre, no cleavage, specific gravity 8.9.
Native nickel is rare but it occurs in iron meteorites and in many different
minerals, often oxidized to form green nickel "blooms",
hydrated nickel salts.
Nickel is weakly magnetic and malleable.
Note the weak attraction to magnets and density of the specimen.
Nickeline, niccolite, NiAs, arsenical nickel
Nickeline has copper red colour with a red tinge, Mohs scale of hardness
5 to 5.5, brown to black streak, metallic lustre, uneven
fracture, specific gravity 7.8, occurs in masses.
The name "nickel" comes from "Old Nick" (the devil) meaning it was
worthless as a copper ore despite its similar colour.
Nickel is used for kitchen vessels, nickel electroplating and tougher
nickel steel for armour plating and machinery parts.
An alloy of copper, zinc and nickel is called "German silver".
An applied magnetic field causes nickel to decrease in length so nickel
wire may be used in some types of computers.
Note the colour, density, streak and sometimes an odour when heated.
Palagonite, mafic volcanic glass, altered by hydration of siderolemane
Rock mineral fertilizer dust containing high levels of Si, Ca and trace
minerals, used in compost-making and soil mixes.
It holds water well so is used in sandy soils.
35.20.31 Platinum, Pt
See: Platinum (Chemistry)
Platinum has steel grey colour of native platinum, but silver-white
colour of pure metal, Mohs scale of hardness 4 to 5.5, steel grey
streak, metallic lustre, no cleavage, jagged fracture and specific gravity
14-19 for native platinum (platina, Spanish diminutive of
silver, plata) and density 21.45 for pure platinum, so one of the heaviest
Platinum does not react with air, water or strong acids (except a mixture
of hydrochloric acid and nitric acid).
Native platinum is very rare and occurs in alluvial deposits as scales
and grains or cubic crystals.
Note the density, colour and hardness of the specimen.
Pyrite, iron pyrite, iron sulfide, FeS2 : See: Iron (II) sulfide (Chemistry)
Iron sulfide, FeS2, iron disulfide, sulfuric pyrites, pyrite,
iron pyrites, fool's gold, marcasite
Pyrite has pale brass yellow colour, Mohs scale of hardness 6 to 6.5,
black green to black brown streak, but green or brown to black
powder, metallic lustre, poor cleavage, conchoidal to uneven fracture,
and specific gravity 4.9-5.2.
It is the most common sulfide mineral and occurs as cubic crystals.
It is found in lining cavities in faults and fractures in ore bodies.
The associated minerals are calcite and rhodocrosite.
It gives out sparks when struck with steel because of the fragments
of sulfur igniting.
Pyrite was used in the old wheel lock firearms to produce the spark
to explode the gunpowder.
Pyrite frequently shows traces of gold, silver, copper, nickel and arsenic.
It can occur in mineral veins where it was commonly mistaken for gold,
"fool's gold", but it may be rich in gold or copper or sulfur.
It is used to manufacture sulfuric acid but is not smelted for iron
Pyrite may be polished and used in jewellery, but it is not malleable.
Pyrite may have characteristic striations on the surfaces of the crystal
Pyrite, iron sulfide, is found in lining cavities in faults and fractures
in ore bodies.
The associated minerals are calcite and rhodocrosite.
Pyrite is not magnetic but is attracted to a magnet.
Pyrite can be used in solar cells instead of silica.
Pyrite crystals were used as crystal detectors in "crystal set" radio
Note the hardness, streak and lustre of the specimen.
Pyromorphite, Pb5Cl(PO4)3, has non-metallic
and resinous to adamantine lustre, Mohs scale of hardness: 3.5-4, and colour
consisting of shades of
green, yellow, brown, grey and occasionally yellow-orange, sub transparent
to translucent, specific gravity 6.5-7.1, colourless streak.
Pyromorphite is the most common lead phosphate, lead chlorophosphate.
It is a secondary mineral from the oxidized zone.
It has a large range of habits and colours including coatings and sprays,
simple hexagonal prisms, stout hexagonal prisms, branching
aggregates, mamillated, botryoidal and colloform masses.
It is found all along the lode outcrop.
The associated minerals are coronadite, cerussite, secondary galena,
Pyrrhotite, FeS, iron sulfide, has metallic lustre, Mohs scale of hardness
4, specific gravity 4.58-4.65, brown-bronze colour, black streak.
It is found in veins, zones and bands in ore bodies.
Pyrrhotite can be weakly magnetic but not at Broken Hill, where the
associated minerals are calcite, galena, and chalcopyrite.
Rhodochrosite, manganese carbonate, MnCO3, is a pink mineral
found in fault zones along with other carbonate minerals, e.g. calcite.
Rhodonite, manganese silicate, MnSiO3, or ([Mn, Ca]SiO3),
specific gravity 3.69, is the most abundant manganese mineral found in the
It has a range of beautiful red pink "rosy" colours.
Rutile, TiO2, titanium (IV) oxide, TiO2, titanium
dioxide, nanopowder, fine powder, Anatase mineral, toxic if inhaled
Titanium (IV) oxide, powder, TiO2, titanium dioxide, colour
white, opacifer, "white out" correction fluid, white pigments for tennis
household white paint, from mineral rutile, ilmenite FeTiO3, food
additive, E171, the three mineral forms are anatase, brookite and rutile.
Rutile (titanium (IV) oxide, titanium dioxide, titania), has black
or yellow to red to orange colour, Mohs scale of hardness 6-6.5,
brown streak, diamond-like lustre, good cleavage in two directions,
conchoidal to uneven fracture, specific gravity 4.25.
Titanium is used in the aerospace industry to produce low density corrosion
Titanium dioxide has replaced lead in lead paint.
Titanium forms a protective layer in air, a passive oxide coating.
Note the lustre, hardness and streak of the specimen.
Scheelite crystals, calcium tungstate, CaWO4, has white to
orange to grey colour, Mohs scale of hardness 4.5-5, white streak, diamond-like
to greasy lustre, poor cleavage, conchoidal to even fracture, and specific
The crystals are usually not water worn, so they keep their characteristic
They are transparent to translucent and may be bright or dull, with
It fluoresces blue in ultraviolet light.
This mineral occurs in veins in granite rocks with cassiterite or fluorspar.
Scheelite is an important ore of tungsten, W, used to increase the hardness
Note the crystal habit, fluorescence, and lustre of the specimen.
35.20.39 Silver, Ag
See: Silver (Chemistry)
Silver has silver white shiny colour that tarnishes to a black colour,
Mohs scale of hardness 2.5-3, silver to white streak, metallic
lustre, no cleavage, jagged fracture, and specific gravity 10.5, if pure,
but 10-12 if impure.
It is malleable and ductile, can be cut into slices, and is one of the
best conductors of electricity.
It is a precious metal ranked next to gold and was once obtained from
natural large masses but now is a by-product from the refining
of lead, zinc, copper and gold.
Silver can be moulded and shaped to form jewellery because of its pure
white colour, softness and toughness.
Silver has massive, wire habit .
The associated minerals are gold and copper.
Silver occurs in a variety of minerals, but most of the silver is found
as trace amounts of silver mineral locked up inside the lead
Sometimes silver occurs as big lumps, nuggets, of the metal itself.
Only silver ever comes out of the ground as a metal.
Lead and zinc are always locked away minerals, as is most of the silver.
Silver was largely used in the photographic industry although it has
uses in jewellery, electronics and silverware.
Note the colour and tarnish of the specimen.
Smithsonite, ZnCO3, calamine, zinc spar, galmei, ZnCO3,
(basic zinc carbonate, ZnCO3.2ZnO.3H2O),
has a non-metallic and vitreous to waxy lustre, Mohs scale of hardness
4-4.5, specific gravity 4.4-4.5, colourless to white to green to
pink to blue colour, colourless streak.
It is used as the main ingredient in zinc sun cream.
Calamine, is used in pink calamine lotion for treating sunburn.
Smithsonite, zinc carbonate, ZnCO3, is a widespread secondary
mineral from the oxidized zones.
It occurs as rounded botryoidal aggregates resembling drops of wax and
as honeycombed masses in ore bodies.
It is the most abundant secondary carbonate after cerussite.
The associated minerals are coronadite and goethite.
It is a widespread secondary mineral from the oxidized zones.
The associated minerals are coronadite and goethite.
It was formerly used to produce brass.
Calamine, Zinc carbonate, ZnCO3, harmful if ingested, calamine,
zinc spar, smithsonite
Note the colour and colourless streak.
Sphalerite, ZnS: See: Zinc
Sphalerite, zinc sulfide, zinc blende, blende, mock ore, mock lead,
black jack, zinc iron sulfide (Zn, Fe)S, has black colour, but other
colours also occur, Mohs scale of hardness 3.5-4, yellow to brown streak,
diamond-like to submetallic lustre, good cleavage
in 6 directions, specific gravity 3.9-4.1.
The crystals may be transparent with brilliant sheen or translucent
to opaque with metallic lustre.
It may glow if crushed, triboluminescent.
Zinc blende frequently occurs in compact masses with quartz, copper
pyrites and galena.
Zinc is used to galvanize iron for roofing, for lining iron "tins" to
prevent rust and in the manufacture of white paint and optical glass.
Sphalerite (zinc sulfide, ZnS) is the main zinc ore mineral at Broken
Good crystalline sphalerite is unusual at Broken Hill.
The colour of sphalerite varies with its impurities.
At Broken Hill it is black, but some rare large crystals have a deep
Note lustre, streak and softness of the specimen.
Stibnite, Sb2S3, antimonite, antimony glance, grey
Stibnite, has grey to silver colour, Mohs scale of hardness 2, dark
grey streak, metallic lustre, cleavage in one direction and specific
Stibnite can mark paper, the crystals are curved and twisted, and it
is the most important source of antimony, an important metal in the
Note the crystal habit of the specimen.
Member of the zeolite group, lamellar zeolite, hydrated sodium calcium
aluminium silicate, Ca(Al2Si7O18).6H2O.
Stilbite, hydrated sodium calcium aluminium silicate, has more than
one chemical formula, e.g. Na2, Ca, K2Al2Si7O18.7H2O,
has white to pink to yellow colour, Mohs scale of hardness 3.5-4, white
streak, glassy to pearly lustre, good
cleavage in one direction, specific gravity 4.56.
Note how thin crystals stick together like a sheaf of wheat, lustre
and density of the specimen.
35.20.44 Sulfur, S
Sulfur has yellow crystals with colour sometimes masked by impurities,
Mohs scale of hardness 2, yellow streak, glassy lustre, poor
cleavage, conchoidal fracture, and specific gravity 2.07 (rhombic).
If held in a warm hand it may crackle, so it should be handled with
It burns with a small blue flame to form sulfur dioxide.
It is given off from volcanoes and deposited by the waters of some geysers
and hot springs.
Sulfur is used in the manufacture of sulfuric acid, insecticides, medicines,
matches, gunpowder and fireworks.
Note the colour, smell, and sensitivity to heat of the specimen.
35.20.45 Tin, Sn
Tin is very rare as native tin in placer deposits and tin is seldom
used by itself.
Specific gravity 7.28.
Bronze is approximately 5% tin and 95% copper.
Other tin alloys include solder and pewter.
Tin is used in the glass industry.
Uraninite, UO2 (with UO3, Th, Pb, pitchblende,
pitch ore), occurs usually as pitch-like masses (not crystals), has dull
grey to black colour
with brown tint, Mohs scale of hardness 5-6, brown to black streak,
metallic to dull lustre or a shine like pitch, poor cleavage,
conchoidal to uneven fracture, and specific gravity 8-10.6.
It is moderately hard and very heavy.
It undergoes radioactive decay to produce radium and helium, and other
Uranium is used in high grades of steel and is also the basic material used in atomic bombs and the world's nuclear power stations.
It is a rare material but large deposits occur.
Note the radioactivity, lustre, colour and streak of the specimen.
35.20.47 Uranium, U
1. Uranium occurs as uranium dioxide, UO2, in the mineral
pitchblende, uraninite, that also contains radium and products of radioactive
Uranium ores usually contain Actinium.
2. Natural uranium is about 0.72% U235 (atomic number 92 + 143 neutrons)
and 99.28% U238 (atomic number 92 + 146 neutrons).
The half life of U235 is smaller than the half life of U238, specific
The uranium decay series involves 14 steps as uranium decays eventually
3. Uranium fission is a nuclear reaction used to produce energy by neutron
bombardment to form krypton-89 and barium-144 and
3 neutrons that can start a chain reaction.
The heat and radiation from the chain reaction must be controlled only
by controlling the chain reaction.
235U92 + 1n0 --> 89Kr36
+ 144Ba56 + 31n0 + λ
uranium-235 + neutron --> krypton-89 + barium-144 + 3 neutrons +
radioactive decay constant
4. Uranium-238 spontaneously decays, first by alpha particle emission,
alpha radiation (α radiation).
238U92 --> 234Th90 +
4He2 + γ
An alpha particle can be shown as 4He2 or
uranium-238 --> thorium-234 + alpha particle + gamma rays
Uranium-238 eventually decays by 14 steps to 206Pb82.
Lead is more stable than the previous radioactive elements in the decay
Wolframite, iron manganese tungstate (Fe, Mn)WO4, has grey
to brown to black colour, Mohs scale of hardness 4-4.5, brown to black
dull lustre, good cleavage in one direction, and specific gravity 7.0-7.5.
Wolframite is an important ore of tungsten, W, used to increase the
hardness of steel.
Note the cleavage, density and lustre of the specimen.
Models, inorganic, Zeolite,
"Scientrific" (commercial website)
See 18.7.69 Zeolite, swimming pools
Zeolite, e.g. tetrapropylammonium (TPA)ZSM-5, is a group of natural
or synthetic hydrated aluminium silicates that appear to boil
when heated in a blowpipe, specific gravity 2.0-2.4.
They retain pores or channels in their crystal structure, easily gain
or lose water, and have a high ion exchange capacity.
Zeolites are used in detergents as water softeners, and as catalysts
for reforming petroleum products.
Sodium aluminosilicates, e.g. albite (NaAlSi3O8),
"Zeolite A", synthetic laundry detergent, Na12Al12Si12O48.
35.20.50 Zinc, Zn
See: Zinc (Chemistry)
Zinc is white to blue grey colour, grey streak, metallic lustre, good
cleavage in one direction, specific gravity 7.1.
It almost never occurs as the metal but combined with sulfur or oxygen.
Zinc is brittle and must be heated to become malleable or ductile.
Zinc occurs mainly as sphalerite (zinc sulfide, ZnS).
At Broken Hill it has a black resinous appearance but rarely shows as
Smithsonite (zinc carbonate, ZnCO3), caused by weathering
and oxidation of ore by groundwater, is found in areas where the ore
body was at or near the surface.
Zinc is used in galvanized coatings of iron and steel.
It is also used in die cast alloy products, pigments and other industrial
and agricultural applications.
Note colour, hardness and density of the specimen.
Zincite, red oxide of zinc, ZnO, is found in metamorphic weathered deposits,
specific gravity 5.66.
Tanzanite is found near Mount Kilimanjaro, Tanzania, specific gravity
It is a variety of the mineral zoisite (Ca2)(Al3)(Si2O7)(SiO4)O(OH),
that has been artificially heated to become a gemstone, which
exhibits trichroism, i.e. alternately sapphire blue, violet, and burgundy
colours, depending on crystal orientation.
Ammolite (aapoak, Kainah, gem ammonite, calcentine, korite), one of
the rarest gemstones, is found in Alberta and on slopes of
Rocky Mountains, is composed of fossilized shells of ammonites, mostly
aragonite crystals as in nacreous pearl shell, specific gravity
The pearly flashes of red, green and blue iridescence from polished
ammolite is caused by interference of light rebounding through
layers of aragonite.
Nacre, CaCO3, mother of pearl, specific gravity 2.68-2.86,
pearls, an inner shell layer of some molluscs, is iridescent because of
tiny plates of
aragonite held within an organic matrix, e.g. chitin, that strengthens
It may produce a blister pearl attached to the interior of the shell,
or a free pearl within the mantle tissues.
35.20.55 Lapis lazuli
Lapis lazuli, ancient intense blue semi-precious stone, lazurite mineral,
(Na, Ca)8[(S, Cl, SO4, OH)2.(Al6Si6O24)],
source of deep blue pigment ultramarine (beyond the sea), often occurs
in crystalline marble, specific gravity 2.7-2.9.
This deep blue pigment much replaced by Prussian blue.
See: Tantalum, Ta, Table of the elements
See: Niobium, Nb, Table of the elements
Coltan, "columbite-tantalite", Niobium and Tantalum metallic ore, from
eastern Democratic Republic of Congo where "conflict tantalum"
is mined by minors and adult workers under adverse conditions to cause
of genocides, heat resistant powder, tantalum holds charge
well so is in capacitors for smart phones, tablet computers and cell
phones circuit boards, and its oxide in insulators.
High cost tantalum has been mined in Australia, Canada and Eritrea.
35.24.1 Make artificial igneous
rocks, alum crystals, sulfur crystals
1. Crystallization of alum solutions is similar to the formation of coarse
grained and fine grained igneous rocks.
Fill a test-tube one quarter full of powdered potash alum, [Al2(SO4)3.K2(SO4).24H2O],
Slowly add just enough boiling water to dissolve the alum.
Hold the test-tube in a flame so that the mixture boils gently.
(a) Pour half the solution into a shallow metal container.
Place a piece of string partly in the liquid and add a seed crystal.
Stir the alum solution in the container so it cools quickly.
(b) Hang another piece of string in the test-tube so that it reaches
the bottom and add a seed crystal.
Place the test-tube where it will cool slowly.
Examine the two solutions the following day and note the sizes of the
2. Melt some sulfur in a test-tube.
Fit a filter paper into a funnel and pour the molten sulfur into it.
As the sulfur cools it begins to solidify, first forming a crust on the
As soon as the crust has formed, remove the filter paper from the funnel
and unfold it, so that the still liquid sulfur in the lower part of
the filter can flow away from the crust.
Note a mass of small crystals on the underside of the crust.
Use a magnifying glass to observe the shape of these crystals.
3. Melt sulfur in a test-tube then pour it into a large beaker of water
so that it solidifies rapidly to form plastic sulfur.
Take it out of the water and examine it after two hours.
The solid sulfur formed is very hard and you cannot see crystals with
a magnifying glass.
However, very tiny crystals may be seen with a microscope.
35.24.2 Make artificial rocks,
1. Use a hammer to grind different coloured sedimentary rocks, keeping
the colours separated.
Put coloured powdered particles in a glass jar as different layers.
Let water trickle down the inside of the jar so as not to disturb the
layering until the water is 1 cm above the sediments.
Put the jar in the sun and let the water evaporate.
Wrap the jar in a thick cloth and break it with a hammer.
2. Mix Portland cement with water and put it in a mould until it hardens.
Break the set cement with a hammer and examine the outside and inside
3. Mix dry cement with twice as much sand or gravel to form concrete.
Add water, mix thoroughly, and place it in a mould.
Leave the concrete to harden for several days.
Break the set concrete with a hammer and examine the outside and inside
Note whether the concrete is easier or harder to break than the Portland
4. Mix plaster of Paris with a small amount of water and put it in a
mould until it hardens.
Stir rapidly or it will harden while being mixed.
Break the set plaster with a hammer and examine the outside and inside surfaces.
Note whether the plaster is easier or harder to break than the Portland
cement or the concrete.
35.24.3 Make artificial rocks,
Fire a shaped piece of clay that has first been dried and put on a piece
of broken pottery and heated it in a large crucible over a
Tourmaline, NaFe3Al6[(OH)4(BO3)3, Si6, O18],
(in pegmatites), double refraction, contains about 10 % boron.