Chemical properties of Rocks and Minerals

Chemical properties of rocks and minerals

Each individual mineral and rock has a distinct chemical composition which can be written as chemical formula. Except for native elements, minerals are salts composed of positively charged cations (e.g. K+, Na+, Ca++, Fe+++) and negatively charged anionic groups (e.g. CO3, PO4). The list below gives the main mineral groups and examples of each corresponding anionic group.

Silicates - are the largest group. About 86% of the earth's volume is silicate. A complex form of other materials often surrounds silicate because of its ability to polymerise. The silicate group has been subdivided into a number of smaller groups using their mineral structures as a basis. These include:

Tectosilicates - quartz, feldspars, zeolites
Phyllosilicates - micas, serpentines, clays, chlorites
Inosilicates - pyroxenes, pyroxinoids
Cyclosilicates - tourmalines, beryl
Sorosilicates - epidote, vesuvianite
Nesosilicates - garnets, olivine, alumino-silicates

Arsenites and vanadates AsO4 and VO4
(Adamite, Erythrite, Mimetite, Olivenite, Carnotite, Vanadinite)
Carbonates CO3
(Calcite, Cerussite, Dolomite, Siderite, Smithsonite)
Halides Cl Cl2 F F2
(Atacamite, Carnallite, Cryolite, Fluorite, Halite)
Native elements Au Ag
(Gold, Silver, Copper, Iron)
Nitrates and borates NO3 and BO3 B3O4
(Nitratine, Chambersite, Inderite, Borax)
Oxides and hydroxides O O2 and OH (OH)2
(Baddeleyite, Corundum, Chrysoberyl, Rutile, Goethite, Manganite)
Molybdates and tungstates MoO4 and WO4
(Ferrimolybdite, Wulfenite, Wolframite)
Phosphates PO4
(Anapaite, Apatite, Brazilianite, Chalcosiderite, Fluorapatite, Herderite, Lazulite)
Silicates SiO4 Si2O4
Sulphides S S2
(Chalcocite, Cinnabar, Galena, Jamesonite, Pyrite, Sphalerite, Stibnite)
Sulphates and chromates SO4 and CrO4
(Anhydrite, Barite, Celestite, Sulphohalite)

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