Descriptive Mineralogy NonSilicates Carbonates Classification of the Minerals

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 Ca. CO 3 Magnesite Mg. CO 3 Siderite Fe. CO 3 Rhodochrosite Mn. CO 3 Smithsonite Zn. CO 3

Calcite Structure • Space Group R-3 c • Divalent cation radius < 1. 00Å

Calcite Ca. CO 3

Calcite Ca. CO 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 Mn. CO 3 Occurrence: Low T Hydrothermal Uses: Mineral Specimens

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

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

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

Aragonite Group • • Aragonite Ca. CO 3 Strontianite Ca. CO 3 Witherite Ba. CO 3 Cerussite Pb. CO 3

Aragonite Structure • Space Group Pbnm • Cation Radius > 1. 00Å

Aragonite Ca. CO 3 Occurrence: High pressure rocks Some shells Boiler scale Uses: None

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

Witherite Ba. CO 3 Occurrence: Low T Hydrothermal Uses: Rat Poison

Witherite transforms at RT from orthorhombic to trigonal • Witherite (Ba. CO 3) • 0 GPa 8. 0 GPa

Cerussite Pb. CO 3 Occurrence: Oxidized Hydrothermal Uses: Minor ore of Pb

Dolomite Group • Dolomite Ca. Mg(CO 3)2 • Ankerite Ca. Fe(CO 3)2

Dolomite Ca. Mg(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 Ce. CO 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 Ce. CO 3 F Occurrence: Pegmatite Uses: Principal Source of Rare Earth Elements

Bastnasite Ce. CO 3 F

Carbonate Periodic Table

Gossans are Oxidized Hydrothermal Deposits