Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references, Fibrous
Conchoidal, Conchoidal, Gemstones of the world (2001)
CaAl 2(Fe3+ ,Al)Si 3O 12(OH)Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
SiO2