Mineralogy Basics

Definition and Classification

• Minerals are naturally occurring inorganic solids with a specific chemical composition and a crystalline structure.
• Classified based on their chemical composition, crystal structure, and physical properties.

Types of Minerals

• Oxides: composed of oxygen and a metal, e.g., iron oxide (rust)
• Silicates: composed of silicon and oxygen, e.g., quartz
• Carbonates: composed of carbon and oxygen, e.g., calcite
• Sulfides: composed of sulfur and a metal, e.g., pyrite
• Halides: composed of a halogen (fluorine, chlorine, etc.) and a metal, e.g., halite (rock salt)

Physical Properties

• Luster: appearance of a mineral in reflected light, e.g., metallic, glassy, earthy
• Streak: color of a mineral in powdered form, e.g., hematite (red-brown)
• Hardness: resistance to scratching, measured on the Mohs hardness scale (1-10)
• Cleavage: tendency of a mineral to break along flat surfaces, e.g., mica
• Density: mass per unit volume, e.g., gold (19.3 g/cm³)

Formation and Occurrence

• Magmatic: formed from the cooling and solidification of magma, e.g., granite
• Metamorphic: formed through the transformation of existing rocks, e.g., marble
• Sedimentary: formed through the accumulation and compression of sediments, e.g., shale
• Hydrothermal: formed through the interaction of hot water and minerals, e.g., quartz veins
• Biogenic: formed through the activities of living organisms, e.g., pearls

Uses and Importance

• Economic: sources of metals, e.g., copper, iron, gold
• Construction: used as building materials, e.g., limestone, marble
• Industrial: used in manufacturing processes, e.g., quartz, feldspar
• Agricultural: used as fertilizers, e.g., potassium, phosphorus
• Medical: used in medical treatments, e.g., calcium, iron