Descriptive Mineralogy Non-Silicates: Carbonates

Classification of the Minerals Non-Silicates –Native Elements –Halides –Sulfides –Carbonates –Sulfates –Phosphates –Oxides –Hydroxides Silicates –Orthosilicates –Sorosilicates –Cyclosilicates –Chain Silicates –Layer Silicates –Tektosilicates

Carbonates Calcite Group Aragonite Group Dolomite Group Other carbonates

Carbonate Periodic Table

Calcite Group Calcite CaCO 3 Magnesite MgCO 3 Siderite FeCO 3 Rhodochrosite MnCO 3 Smithsonite ZnCO 3

Calcite Structure Space Group R-3c Divalent cation radius < 1.00Å

Calcite CaCO 3

Occurrence: Sedimentary: Detrital and Evaporite limestones Metamorphic: Marble Low temperature hydrothermal. Igneous: Carbonatites, Kimberlites Uses: Building stone, Sculpture, Gravel and paving Acid mine drainage mitigation

Rhodochrosite MnCO 3 Occurrence: Low T Hydrothermal Uses:Mineral Specimens

Siderite FeCO 3 Occurrence:Low temperature hydrothermal. Use; Minor ore of Fe

Magnesite MgCO 3 Occurrence: olivine weathering Uses:Chalk CO 2 Sequestration?

Smithsonite ZnCO 3 Occurrence: Oxidized Hydrothermal (after sphalerite) Uses:Minor ore of Zn

Aragonite Group Aragonite CaCO 3 Strontianite CaCO 3 Witherite BaCO 3 Cerussite PbCO 3

Aragonite Structure Space Group Pbnm Cation Radius > 1.00Å

Aragonite CaCO 3 Occurrence: High pressure rocks Some shells Boiler scale Uses:None

Strontianite SrCO 3 Occurrence: Low T Hydrothermal Uses:Principal source of Sr (used in fireworks, ammunition, flares)

Witherite BaCO 3 Occurrence: Low T Hydrothermal Uses:Rat Poison

Witherite transforms at RT from orthorhombic to trigonal Witherite (BaCO 3 ) 0 GPa8.0 GPa

Cerussite PbCO 3 Occurrence: Oxidized Hydrothermal Uses:Minor ore of Pb

Dolomite Group Dolomite CaMg(CO 3 ) 2 Ankerite CaFe(CO 3 ) 2

Dolomite CaMg(CO 3 ) 2 Occurrence: Sedimentary, Igneous (carbonantites) Uses:None

Other Carbonates Malachite Cu 2 (CO 3 )(OH) 2 Azurite Cu 3 (CO 3 ) 2 (OH) 2 Bastnasite CeCO 3 F Bastnasite REECO 3 F

Malachite Cu 2 CO 3 (OH) 2 Occurrence: Low T Hydrothermal Supergene Cu Uses:Minor ore of Cu, gems and ornaments

Azurite Cu 3 (CO 3 ) 2 (OH) 2 Occurrence: Low T Hydrothermal Supergene Cu Uses:Minor ore of Cu, gems and ornaments

Bastnasite CeCO 3 F Occurrence: Pegmatite Uses:Principal Source of Rare Earth Elements

Bastnasite CeCO 3 F

Carbonate Periodic Table

Gossans are Oxidized Hydrothermal Deposits