Chemical composition: calcium phosphate
Hardness: 2 - 3
Ivory originally only referred to the material of the elephant's tusk. Today it is also the teeth of the hippopotamus, narwhal, walrus, wild boar, and fossilized mammoth. Since 1989, there has been a worldwide ban on ANY trade in elephant's ivory.
Chemical composition: lignite
Hardness: 2.5 - 4
Jet is a bituminous coal that can be polished
Vitreous pink to lilac color.
Variety of: Spodumene
Chemical Composition: LiAlSi2 O6, Lithium Aluminum Silicate
Hardness: 6.5 - 7
It displays a particular type of iridescence on a dark to light smoke gray background.
Chemical Composition: NaAlSi3O8 to CaAl2Si2O8 (Sodium Calcium Aluminosilicate)
Hardness: 6 - 6.5
Chemical Composition: (Na, Ca)8Al6Si6O24(S, SO4) , Sodium Calcium Aluminum Silicate Sulfur Sulfate
Hardness: 5 - 5.5
Location: Taquaral City Minas Gerais, Brazil
Chemical Composition: KLi2Al(Al, Si)3O10(F, OH)2, Potassium lithium aluminum silicate hydroxide fluoride
Also known as the "Tantric Linga"
"Crypto Crystalline Quartz"
Location: Zaire, Africa
Chemical Composition: Cu2(CO3)(OH)2, Copper Carbonate Hydroxide
Mesolite on Apophyllite
Location: Poona India
Chemical Composition of Mesolite: Na2Ca2Al6Si9O30 - 8H2O, Hydrated sodium calcium aluminum silicate
Hardness of Mesolite: 5 - 5.5
Chemical Composition of Apophyllite: (K,Na)Ca4Si8O20(F,OH) - 8H2O, Hydrated Potassium Calcium Sodium Silicate Fluoride Hydroxide
Hardness of Apophyllite: 4.5 - 5
Location: Czech Republic
Chemical Composition: mostly silica glass with impurities of magnesium, iron and other elements
Hardness: 5 - 6
Chemical Composition: KAISi3O8
Hardness: 6 - 6.5
Location: Kunar, Afghanistan
Variety of: Beryl
Chemical Composition: Be3 Al2 Si6 O18
Hardness: 7.5 - 8