Stone	Formula	Group	Other Information
	Talc	Mg3Si4O	Silicates	colourless-softest material
	Thulite	Ca2Al3(SiO4)3OH	Silicates	pink-a variety of zoisite-contains Mn impurity
	Tigers Eye	SiO2	Silicates	yellow to brown-rare-stained by Fe oxides
	Topaz	Al2SiO4(F,OH)2	Silicates	colourless-coloured by impurities e.g. Fe or Cr
	Turquoise	CuAl6(PO4)4 (OH)84-5H2O	Phosphates	blue-found mainly in dry environments
	Turritella Agate	SiO2	Oxides	form of agate
	TV Stone	NaCaB5O65H2O	Borates	colourless-deposited by evap. in salt water
	Unakite	variable	Metamorphic	green with red patches-no crystal structure
	Uvarorite	Ca3Cr2(Si)4)3	Silicates	bright green-occurs in serpentine rocks-type of garnet
	Vanadinite	Pb5(VO4)3Cl	Vanadates	bright red/orange red-industrial source of vanadinite
	Vedelite	variable	Silicates	green-a form of tourmaline
	Verdite	K(Al,Cr)3Si3 O10(OH)2	Silicates	green-member of the mica group-a fuchsite
	Vesuvianite	Ca10(Mg,Fe)2Al4 Si9O34(OH)4	Silicates	colourless
	Volcanic Bomb	-	Extru Ign	clots of lava-fine grained
	Wood Opal	SiO2nH2O	Oxides	variable colour-compressed fallen tree matter
	Yellow Chalcedony	SiO2	Oxides	yellow-colour due to Fe oxide impurities-form of quartz
	Zeolites	variable	Silicates	variable colour-unusual crystal structure
	Zircon	ZrSiO4	Silicates	colourless-source of zirconium
	Zoisite	Ca2Al3(SiO4)3OH	Silicates	colourless

Chemical Symbols