What is a Mineral? • Naturally-formed solid substance with a crystal structure Pyromorphite
What do all minerals have in common? All: • Are formed by natural processes. • Are NOT alive and NEVER were alive • Have a definite volume and shape • Are elements or compounds with a unique chemical makeup • Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)
Watch “Crystals” by Brainpop… • .What element are diamonds made from? • . What do all crystals have in common?
Groups of Minerals • Minerals are grouped by the elements they are made of. Beryl (Emerald) Calcite Amethyst
Silver Copper Diamond Gold Iron Ruby
BariteBaSo4 Barite on CalciteBaSo4 / CaCO3
How do minerals form? • 1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle)) • Fast Cooling = No Crystals (mineraloids) • Medium Cooling = small crystals • Slow Cooling = large crystals
How do minerals form? • 2) Elements dissolved in liquids (usually water)
Physical Properties of Minerals(can be used to identify the mineral) Color • Can be misleading • Can vary with the type of impurities
Physical Properties of Minerals(can be used to identify the mineral) Luster • Surface reflection • metallic = shiny like metal • non-metallic = dull, non-shiny surface Pyrite has a metallic luster Calcite has a non-metallic luster
Physical Properties of Minerals(can be used to identify the mineral) Streak • The color of the powdered form of the mineral • The color of the streak can be different than the mineral • Minerals must be softer than the streak plate
Streak…can help identify quartz BUT... http://www.childrensmuseum.org/geomysteries/cube/b3.html
Physical Properties of Minerals(can be used to identify the mineral) Hardness • How easily a mineral scratches materials • Mohs Hardness Scale • Scale from 1 (softest) to 10 (hardest) • Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)
Find out more… • “Electronic” Hardness Test http://www.childrensmuseum.org/geomysteries/cube/b2.html
Physical Properties of Minerals(can be used to identify the mineral) Cleavage & Fracture • The way the mineral breaks • Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape • Fracture—minerals that break at random with rough or jagged edges
1. 4. 3. 2. Cleavage or Fracture?
Physical Properties of Minerals(can be used to identify the mineral) Other Properties • Specific gravity (*excellent clue to mineral’s identity) • Attraction to magnets • Bending of light • Reaction with hydrochloric acid • Smell & taste http://www.childrensmuseum.org/geomysteries/cube/b4.html
Watch Brainpop—“Mineral Identification” • . If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail. • 2. What is luster?