Glossary T-Z

Tanzanite 

Location: Tanzania, Africa
Variety of: Zoisite
Chemical Composition: Ca2Al3(SiO4)3(OH), Calcium Aluminum Silicate Hydroxide
Hardness: 6.5 - 7

 

Tigereye

There are yellow, blue, and red tigereye.
Location: Australia, Burma, India, Namibia, South Africa, the United States, Brazil, Canada, China, Korea and Spain
Variety of: Quartz
Chemical Composition: NaFe(SiO3)2 Sodium and iron with silicon dioxide (quartz)
Hardness: 6.5 - 7

 

Topaz

November Birthstone
Location:  Brazil, United States, Madagascar, Myanmar (Burma), Namibia, Zimbabwe Mexico, Sri Lanka, Pakistan, Russia, and China
General composition: Al₂SiO₄(F,OH)₂
Hardness: 8

 

Black Tourmaline

Alternate October Birthstone
Location: Brazil and many parts of Africa, including Tanzania, Nigeria, Kenya, Madagascar, Mozambique, Malawi, and Namibia.
General composition: (Na, Ca)(Li, Mg, Al)(Al, Fe, Mn)6(BO3)3(Si6O18)(OH)4
Hardness: 7.0 - 7.5

 

Tourmaline (Watermelon/Bi-color)

Alternate October Birthstone
Location:  Brazil, Nigeria, Madagascar, Afghanistan and the United States
General composition: (Na, Ca)(Li, Mg, Al)(Al, Fe, Mn)6(BO3)3(Si6O18)(OH)4
Hardness: 7.0 - 7.5

 

Turquoise

Location: Worldwide, U.S., Mexico, Iran, Chile, China, and Tibet
Chemical Composition: CuAl6(PO4)4(OH)8*5(H2O), Hydrated Copper Aluminum Phosphate
Hardness: 5 - 6

 

Uvarovite 

Green Garnet

Location: Russia, USA, Italy, Turkey

Vitreous, resinous green.

Chemical Composition: Ca3Cr2(SiO4)3, Calcium Chromium Silicate

Hardness is 6.5 - 7

 

Vanadinite

Location: Mibladen Mine

Morocco, USA

Sub-resinous/sub-adamantine orange, red, brown, yellow, etc.

Chemical Composition: Pb5(VO4)3Cl , Lead Chlorovanadate

Hardness: 3

 

Vivianite 

Location: Ukraine, UK, USA
Chemical Composition: Fe3(PO4)2-(H2O)8, Hydrated Iron Phosphate
Hardness: 1.5 - 2

 

Wavellite 

Location: Arkansas
Chemical Composition: Al3(PO4)2(OH)3-(H2O)5, Hydrated Aluminum Phosphate Hydroxide
Hardness: 3.5 - 4

 

Wulfenite 

Location: Příbram, Czech Republic; Yuma County, Ariz., U.S.; and Mapimi, Durango, Mex. Other localities include Germany, Austria & more
Chemical Composition: PbMoO4, Lead Molybdate
Hardness: 3

 

Zincite

Location: USA, Poland
Chemical Composition: (Zn,Mn)O
Hardness: 4

 

 

Zircon

December Birthstone
Location: Kunar, Afghanistan, Australia, India, Brazil, USA
Chemical Composition: ZrSiO4, Zirconium Silicate
Hardness: 7.5