What Is A Mineral? Characteristics and properties used to identify minerals. What are characteristics of minerals? Solid Formed in nature Non-living Crystalline structure Particles line up in a repeating pattern What are the Six Physical Properties of Minerals? Used to identify all minerals 1. Color The surface color of the mineral Minerals come in a variety of colors Examples of Mineral Colors 2. Luster The way a surface reflects light. (glassy, metallic, waxy, shiny, etc.) Examples of Luster Metallic Looks like metal Pearly Looks like a pearl Vitreous/Glassy Looks like glass Dull Non-reflective Resinous Look of dried glue Earthy Looks like dried mud 3. Streak The color of the mineral in powdered form. Streak color and mineral color are often different. Examples: Hematite – brick red Galena – steel gray Pyrite – brassy yellow or black Olivine – white Feldspar – white Talc – white Gypsum – colorless Examples of Streak 4. Cleavage & Fracture Cleavage = tendency of minerals to break along a flat surface. Fracture = tendency of minerals to break unevenly along a curved or irregular surface Examples of Cleavage Cube or cubic Octahedron or Octahedral Pinacoid – 2 parallel faces Pyramid Dome Prism Examples of Fracture Conchoidal Jagged Subconchoidal Splintery Uneven Earthy 5. Hardness A mineral’s resistance to being scratched. Any mineral with a higher hardness rating can scratch a mineral with a lower hardness rating. Diamond is the hardest natural substance known to humans. Moh’s Hardness Scale 1. 2. Talc Gypsum --fingernail at 2.5 3. Calcite --copper (old penny) at 3.5 4. Fluorite 5. Apatite --window glass or typical knife blade at under 5.5 6. Orthoclase --streak plate or good steel file at over 6.5 7. Quartz 8. Topaz 9. Corundum 10. Diamond 6. Density How much matter there is in a given amount of space. Galena – specific gravity = 7.4 to 7.6 What are some Special Properties? Fluorescence Magnetism Taste Light refraction Odor What are some uses of minerals? Coins Jewelry Electrical wires Batteries Paint Steel Building materials etc. Rocks are made out of minerals, but minerals are not made of rocks.