3.1 Mineral properties and identification

Minerals have unique physical properties that help geologists identify them. These properties include color, luster, streak, hardness, cleavage, fracture, and specific gravity. Each characteristic provides clues about a mineral's composition and structure.

Identifying minerals involves various tests and observations. Geologists use visual inspection, streak tests, hardness tests, and chemical reactions to narrow down possibilities. These properties also determine how minerals are used in industry, technology, and everyday life.

Physical Properties of Minerals

Physical properties of minerals

Top images from around the web for Physical properties of minerals

• 

  Sam and Dave Dig a Hole – Primary Source Pairings View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology – 2nd Edition View original

  Is this image relevant?

• 

  Sam and Dave Dig a Hole – Primary Source Pairings View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology View original

  Is this image relevant?

1 of 3

Top images from around the web for Physical properties of minerals

• 

  Sam and Dave Dig a Hole – Primary Source Pairings View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology – 2nd Edition View original

  Is this image relevant?

• 

  Sam and Dave Dig a Hole – Primary Source Pairings View original

  Is this image relevant?

• 

  2.6 Mineral Properties – Physical Geology View original

  Is this image relevant?

1 of 3

• Color varies due to impurities or chemical composition affects external appearance (copper, malachite)
• Luster describes light reflection off mineral surface metallic shiny like metal non-metallic dull waxy pearly or glassy (pyrite, quartz)
• Streak reveals color of mineral's powder when scratched on unglazed porcelain often more consistent than apparent color (hematite, pyrite)
• Hardness measures resistance to scratching using Mohs scale 1 (talc) to 10 (diamond)
• Cleavage shows mineral's tendency to break along specific planes described by number of directions and angle between planes (mica, halite)
• Fracture describes mineral breaks not along cleavage planes types include conchoidal hackly splintery earthy (quartz, chalcopyrite)
• Specific gravity compares mineral's density to water measured using balance and water displacement (gold, pumice)

Mineral identification tests

• Visual inspection observes color luster and crystal form (amethyst, pyrite)
• Streak test scratches mineral on streak plate to observe powder color (hematite, malachite)
• Hardness test uses Mohs scale objects to determine scratch resistance (calcite, quartz)
• Cleavage and fracture examination observes how mineral breaks when struck (mica, obsidian)
• Specific gravity estimation compares mineral's weight to similarly sized objects (galena, pumice)
• Chemical tests include acid test for carbonates fizzing with dilute HCl (calcite, dolomite)
• Magnetism check tests if mineral is attracted to a magnet (magnetite, hematite)
• Fluorescence observes mineral under ultraviolet light (fluorite, calcite)

Importance of mineral properties

• Industrial applications utilize hardness for abrasives (diamond, corundum) and strength for construction materials (quartz, feldspar)
• Gemstones valued for optical properties color luster clarity and durability hardness toughness (ruby, sapphire)
• Technological uses exploit electrical conductivity (copper, gold) and magnetic properties (magnetite)
• Environmental applications leverage porosity for water filtration (zeolites) and absorption capacity for soil remediation (clay minerals)
• Energy sector relies on fluorescence for fossil fuel exploration (calcite) and radioactive properties for nuclear energy (uraninite)

Differentiation of minerals

• Systematic approach observes multiple properties to narrow down possibilities uses elimination process based on unique property combinations
• Key distinguishing features include hardness and acid reaction for quartz vs calcite streak color and hardness for pyrite vs gold color and streak for muscovite vs biotite
• Chemical composition categorizes silicates with Si-O tetrahedra carbonates with CO3 groups reacting with acid and sulfides with metallic luster often heavy
• Crystal structure classifies isometric cubic system (halite, pyrite) hexagonal six-sided prisms (quartz, beryl) monoclinic non-right angles (orthoclase)
• Optical properties encompass birefringence double refraction in calcite and pleochroism color change with crystal orientation (tourmaline)