Minerals 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