- 1. Quartz is an essential constituent of granite and other
felsic igneous rocks. It is very common in sedimentary rocks such
as sandstone and shale and is also present in variable amounts as
an accessory mineral in most carbonate rocks.
2. On exposure to air, chalcopyrite oxidises to a variety of
oxides, hydroxides and sulfates. Associated copper minerals include
the sulfides bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS),
digenite (Cu9S5); carbonates such as malachite and azurite, and
rarely oxides such as cuprite (Cu2O). Chalcopyrite is rarely found
in association with native copper. 3. Actinolite is an amphibole
silicate mineral with the chemical formula Ca2(Mg,Fe)5Si8O22(OH)2.
4. Crocoite is a mineral consisting of lead chromate, PbCrO4. It is
sometimes used as a paint, being identical in composition with the
artificial product chrome yellow 5. Aurichalcite is a carbonate
mineral, usually found as a secondary mineral in copper and zinc
deposits. 6. The name is derived from the Greek, stauros for cross
and lithos for stone in reference to the common twinning.
Staurolite is one of the index minerals that are used to estimate
the temperature, depth, and pressure at which a rock undergoes
metamorphism. 7. Cuprite is an oxide mineral composed of cooper(I)
oxide Cu2O, and is a minor ore of cooper. 8. Corundum is a
crystalline form of aluminium oxide (Al2O3) with traces of iron,
titanium and chromium. It is one of the naturally clear transparent
materials, but can have different colors when impurities are
present 9. Agate is one of the most common materials used in the
art of hardstone carving, and has been recovered at a number of
ancient sites. Agate is a microcrystalline variety of silica
chiefly chalcedony, characterised by its fineness of grain and
brightness of colour. 10. Bournonite is a sulfosalt mineral
species, a sulfantimonite of lead and copper with the formula
PbCuSbS3. 11. Erythrite or red cobalt is a secondaryhydrated cobalt
arsenate mineral. The color is crimson to pink and occurs as a
secondary coating known as cobalt bloom on cobalt arsenide
minerals. 12. Dioptase is an intense emerald-green to bluish- green
copper cyclosilicate mineral. It is transparent to translucent. 13.
Cinnabar or cinnabarite (red mercury(II) sulfide (HgS), native
vermilion, is the common ore of mercury. 14. Natrolite is a
hydrated sodium and aluminium silicate. Natrolite is usually white
or colorless, but sometimes reddish or yellowish. 15. Psilomelane,
also known as black hematite consists of hydrous manganese oxid e
with variable amounts of barium and potassium. 16. Realgar, is an
arsenic sulfide mineral, also known as "ruby sulphur" or "ruby of
arsenic. It is orange-red in colour and burns with a bluish flame
releasing fumes of arsenic and sulfur. 17. Smithsonite, or zinc
spar, is zinc carbonatea mineral ore of zinc. Smithsonite is a
variably colored trigonal mineral which only rarely is found in
well formed crystals. 18. Xenotime is a rare earth phosphate
mineral, whose major component is yttrium orthophosphate (YPO4) 19.
Gypsum is a very soft sulfate mineral composed of calcium sulfate
dihydrate, with the chemical formula CaSO42H2O 20. March 2012
