Introduction to Mineralogy and Mineral Properties

Mineralogy

Mineralogy is the science that studies the physical and chemical properties of minerals.

Mineral Classifications

Primary Minerals

Primary minerals are minerals found in their original deposits. An example is pyrite (FeS₂), known for its gold-like color and luster.

Secondary Minerals

Secondary minerals form from chemical reactions involving primary minerals. Anglesite (PbSO₄) is a secondary mineral derived from the primary mineral galena (PbS).

Solid Structures

Crystalline Solids

Crystalline solids have particles arranged in an orderly and regular pattern in three dimensions, following a defined geometric structure.

Amorphous Solids

Amorphous solids have particles arranged randomly, similar to the structure of liquids, resulting in a shapeless form.

Most solid materials on Earth are crystals, such as quartz (SiO₂). Exceptions include amorphous solids like volcanic rocks. Crystals are built from a unit cell that repeats infinitely in three dimensions.

Mineral Groups

• Native Elements: Diamond (C), gold (Au), silver (Ag)
• Sulfides: Pyrite (FeS₂), chalcopyrite (CuFeS₂), galena (PbS)
• Halides: Halite (NaCl), fluorite (CaF₂)
• Oxides and Hydroxides: Corundum (Al₂O₃), limonite (FeO(OH))
• Carbonates: Calcite (CaCO₃), dolomite (CaMg(CO₃)₂)
• Sulfates, Tungstates, Molybdates, and Chromates: Gypsum (CaSO₄·2H₂O), wolframite ((Fe,Mn)WO₄), crocoite (PbCrO₄)
• Phosphates, Arsenates, and Vanadates: Turquoise (CuAl₆(PO₄)₄(OH)₄·4H₂O)
• Silicates: Quartz (SiO₂), opal (SiO₂·nH₂O), talc (Mg₃Si₄O₁₀(OH)₂)

Crystal Systems

Examples of crystal systems include cubic (pyrite), tetragonal (cassiterite), trigonal (siderite), hexagonal (beryl), rhombic (sulfur), monoclinic (gypsum), and triclinic (axinite).

Hardness Scale

• Very Soft: Gypsum powder
• Soft: Calcite, fluorite, apatite
• Hard: Orthoclase, quartz, topaz, corundum
• Very Hard: Diamond

Mineral Processing

• Milling: Ore is crushed and ground to reduce particle size to 20-25mm.
• Leaching: Ground mineral is treated with sulfuric acid to obtain a copper sulfate solution.
• Extraction: Organic solvents remove impurities from the copper sulfate solution, increasing concentration to 45 g/L.
• Electrowinning: Electrolysis produces 99.98% pure copper cathode.
• Flotation: Frothing agents separate copper particles from impurities.
• Filtration and Drying: Water is removed, leaving less than 5%.
• Molding: High temperatures refine the copper, producing 99.5% pure blister copper.
• Fire Refining: Blister copper is further refined to remove oxygen, resulting in 99.9% pure copper.