Stone	Formula	Group	Other Information
	Abalone	Variable	Organic	colourless-shell material found in warm waters
	Actinolite	Ca2(Mg,Fe)5 Si8O22(OH)2	Silicates	green-variety of nephrite
	Agate	SiO2	Silicates	colour depends on impurities-form of chalcedony
	Alabaster	Ca SO42H2O	Sulphates	usually white-variety of gypsum-forms by evaporation
	Almandine	Fe3Al2(SiO4)3	Silicates	red-a garnet
	Amazonite	KAlSi3)8	Silicates	green/turq-a feldspar
	Amber	-	Organic	yellow/brown-fossil resin of coniferous trees
	Amethyst	SiO2 with Fe	Oxides	violet-variety of quartz-colour due to presence of Fe oxide
	Andradite	Ca3Fe2Si3O12	Silicates	green/black-member of the garnet family
	Angelite	CaSO4	Sulphates	aka anhydrate light blue-similar to gypsum
	Annabergite	Ni3(AsO4)2 8H2O	Arsenates	white/green-forms in nickel veins
	Apatite	Ca5(PO4)3 (F,Cl,OH)	Phosphates	colourless (appears blue/green)-source of phosphorous
	Apophyllite	KCa4Si8O20 (FOH)8H2O	Silicates	white/colourless-usually transparent
	Aquamarine	Be3Al2Si6)18	Oxides	blue variety of beryl
	Aragonite	CaCO3	Carbonates	colourless-similar to calcite-different crystal structures
	Arkose	-	Sedimentary	a sandstone-(feldspar and quartz)-forms in bedding layers
	Astrophyllite	(K,Na)3 (Fe,Mn)7Ti2Si8 O24(O,OH)7	Silicates	forms bladed crystals-bronze to golden yellow
	Atacamite	Cu2Cl(OH)3	Halides	green-an evaporite-source of copper
	Augite	(Ca,Mg,Fe )2Si2O6	Silicates	dark green/black-a pyroxene-formed beneath surface
	Aventurine	SiO2 with inclusions	Oxides	brown/green-colour due to inclusions
	Azurite	Cu3(CO3) 2(OH)2	Carbonates	blue-source of copper-known as blue malachite
	Baryte	BaSO4	Sulphates	white-source of barium
	Basalt	-	Extru Igneous	black/brown-formed from solidified lava
	Beryl	Be3Al2Si6O18	Silicates	colourless-source of beryllium
	Biotite	K(Mg,Fe)3Al Si3O10(OH,F)2	Silicates	black/brown-mica

Chemical Symbols