Calcite
carbonate
CaCO3
soft; white
ig, sed, meta
Dolomite
carbonate
CaMg(CO3)2 soft; white shell fragment look; grouped; tan sed; limestones, dolomites meta; high T meta, low T hydroT veins
Azurite
carbonate
Cu3(CO3)2(OH)2 soft; light blue dull, uneven bright blue color sed; meta; secondary min in oxidation zone of Cu deposits
Siderite
carbonate
FeCO3 soft; white/brown vitreous to dull; brown uneven ig, sed, meta; sed beds, med to low T hydroT, peg
Malachite
carbonate
Cu2CO3(OH)2 soft; light green dull, bright green uneven sed, meta; secondary min in oxidation zone of Cu deposits
Rhodochrosite
carbonate
MnCO3 soft; white vitreous; pink uneven ig, sed, meta; hydroT veins associated with sulfides; peg
Gypsum
CaSO x 2H2O soft; white long crystals uneven colorless, brown, grey dull to vitreous sed; deposits, clay; ig; traprock
Anhydrite
CaSO4 soft; white dull to vitreous uneven white/grey sed; rock layers, salt domes; ig traprock
Celestite
SrSO4 soft larger crystals light blue/colorless sed; limestone
Barite
BaSO4 soft; white vitreous heavy uneven white/orange sed, meta
Forsterite
olivine group
Mg2SiO4 hard uneven; small crystals vitreous green ig; mafic to ultramafic
Pyrope
garnet group
Mg3Al2Si3O12 vitreous clear cs dark red ig; intrusive, meta; high P rocks
Grossular
garnet group
Ca3Al2Si3O12 larger crystals hard good cs vitreous pink, green meta; contact, skarns
Zircon
ZrSiO4 hard med to large crystals vitreous uneven grey/clear/light purple/brown ig; granite peg, meta; high grade
Andalusite
Al silicate group
Al2SiO5
cross section crosses
brown with tannish white, yellowish brown
ig; granite peg, sed; alluvial deposits, meta; hydroT replacement deposits
Kyanite
Al silicate group
Al2SiO5 splintery elongated; diff directions vitreous light blue to darker ig; granite peg, meta; schists/gneisses
Sillimanite
Al silicate group
Al2SiO5 splinteryish; fibrous slightly vitreous, grainy uneven grey/brown/black meta; schists/gneisses
Staurolite
Fe2Al9Si4O22(OH)2 perpendicular crosses hard dull, uneven brown/black meta; schists/gneisses
Sphene (titanite)
CaTiSiO5 vitreous can scratch glass some conchoidal brown; kind of translucent ig; peg, sed, meta; skarns, contact
Topaz
Al2SiO4(F,OH)2 hard vitreous good cs light brown, transparent ig; granite peg
Fayalite
olivine group
Fe++2SiO4 hard uneven; small crystals vitreous green ig; mafic to ultramafic
Almandine
garnet group
Fe3Al2Si3O12 hard vitreous conchoidal dark red, brownish parts ig; peg, sed; alluvial fans, meta; contact