Earth Space Science Chapter 4 Minerals Mineral Characteristics

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Earth & Space Science Chapter 4 Minerals

Earth & Space Science Chapter 4 Minerals

Mineral Characteristics Naturally occurring Inorganic (has never been alive) Solid Specific chemical composition (can

Mineral Characteristics Naturally occurring Inorganic (has never been alive) Solid Specific chemical composition (can be an element or a compound) • Atoms are arranged in a regular crystal structure • • Name some minerals…. Is coal a mineral? Salt? Sugar? Glacial ice? Natural gas? Diamond?

How Minerals Form • Molten magma cools and crystallizes – If cooling is slow,

How Minerals Form • Molten magma cools and crystallizes – If cooling is slow, large crystals form – If cooling is fast, small crystals form • Minerals can form from solutions – Water can evaporate, leaving mineral crystals behind – Minerals can precipitate from a saturated solution

Mineral Identification • Luster (metallic or nonmetallic)

Mineral Identification • Luster (metallic or nonmetallic)

Mineral Identification • Color (not always reliable for identification)

Mineral Identification • Color (not always reliable for identification)

Mineral Identification • Streak color (scrape against a ceramic tile)

Mineral Identification • Streak color (scrape against a ceramic tile)

Mineral Identification • Hardness (how easily it is scratched)

Mineral Identification • Hardness (how easily it is scratched)

Mineral Identification • Cleavage/fracture (does it break evenly or with jagged edges

Mineral Identification • Cleavage/fracture (does it break evenly or with jagged edges

Mineral Identification • Texture • How does it feel? (smooth, rough, glassy, soapy, greasy)

Mineral Identification • Texture • How does it feel? (smooth, rough, glassy, soapy, greasy) • Feel these minerals: – Quartz (smooth/glassy) – Graphite (greasy) – Talc (soapy)

Mineral Identification • Crystal structure

Mineral Identification • Crystal structure

Mineral Identification • Specific Gravity/Density

Mineral Identification • Specific Gravity/Density

California in 1849…. • How would you tell the difference between gold and pyrite

California in 1849…. • How would you tell the difference between gold and pyrite (fool’s gold)?

Special Properties Taste (halite) Smell (sulfur) Magnetism (magnetite) Double refraction (calcite-Iceland spar) Effervescence—bubbles—in acid

Special Properties Taste (halite) Smell (sulfur) Magnetism (magnetite) Double refraction (calcite-Iceland spar) Effervescence—bubbles—in acid (calcite/carbonates) • Fluorescence—glow in the dark (fluorite) • Iridescence—color changing (labradorite, bornite) • • •

Mineral Groups Sharing similar chemical composition: • Silicates: quartz, feldspar, mica • Carbonates: calcite,

Mineral Groups Sharing similar chemical composition: • Silicates: quartz, feldspar, mica • Carbonates: calcite, dolomite, azurite • Metal oxides: hematite, magnetite • Others: – Sulfides: pyrite – Halides: halite – Native elements: copper, silver, etc.

Economically Important Minerals • Ore: a mineral that contains a useful substance that can

Economically Important Minerals • Ore: a mineral that contains a useful substance that can be mined profitably – Hematite (iron) – Bauxite (aluminum) • Gem: a mineral prized for its rarity and beauty – Ruby – Emerald – Diamond