USA, Southern and central Africa, green, blue, China, India, USA, Italy, green, blue, China, India, USA, Italy
Southern and central Africa
Uneven, Uneven, Gemstones of the world (2001) More from other references
Conchoidal, Conchoidal, Gemstones of the world (2001)
H 4Mg 3Si 2O 9Walter Schumann , Gemstones of the world (2001) More from other references
SiO 2 · nH 2OWalter Schumann , Gemstones of the world (2001)