The Chemical Classification of Gems & Minerals
From The Gemology Project
The Chemical Classification of Gems & Minerals
Class | Description |
---|---|
Class I: Pure Elements | Metals, alloys, semi-metals and non-metals |
Class II: Sulfides | Sulfur is the principal anion: includes tellurides and arenides |
Class III: Halides | Halogen elements are anions: F, Cl, Br |
Class IV: Oxides | Oxygen is the principal anion, included hydroxides in which the hydroxyl radical (OH) acts as the anion |
Class V a:Carbonates | Carbonate radical (CO3) is the principal anion |
Class V b:Borates | Borate radical (BO3) and boate groups are anions |
Class VI a:Tungstates | Anions are principally WO4 |
Class VI b:Sulphates | sulphate radical (SO4) is the principal anion |
Class VII: Phosphates | Anions are principally PO4 |
Class VIII: Silicates | Silicate groups as anions combining with other elements: includes silica SiO2 |