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Discover the fascinating world of minerals - naturally-formed substances with unique properties. Learn about their formation processes, classification methods, and how to identify them based on physical properties like color, luster, streak, hardness, cleavage, and fracture. Dive into the diverse mineral groupings, including Silicates, and gain insights into their crystal structures. Unearth the beauty and complexity of minerals through this comprehensive guide.
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DSL #27 Identify each statement as either True or False. • Fossil fuels formed millions of years ago from decayed plants and animals. • Most places have winds strong enough to generate electricity. • All minerals are solids, but not all solids are minerals. • The word crystalline means that atoms are arranged in a repeating pattern.
What is a Mineral? • Naturally-formed solid substance with a crystal structure Pyromorphite
What do all minerals have in common? • Formed by natural processes. • Are Inorganic • Have a unique chemical composition (makeup) • Have a crystalline shape- they have a definite volume and shape
How are Minerals classified or grouped? • 90 elements occur naturally in the Earth’s crust. • About 98% of the crust is made of only 8 of these elements • The most common minerals belong to the Silicates Beryl (Emerald) Amethyst Calcite
MICA Quartz
Silver Copper Ruby Diamond Gold Iron
How do minerals form? There are 2 ways that crystals form: • The cooling of hot, liquid rock called magma causes compounds to combine • Rapid Cooling = Small Crystals • Slow Cooling = Large crystals • The evaporation of water that has minerals dissolved in it
How do we identify Minerals? • We look at Physical Properties • These include: • Color/Appearance • Luster • Streak • Hardness • Cleavage/Fracture
Physical Properties of Minerals(can be used to identify the mineral) Color • Can be misleading • Many minerals will have a similar appearance, but will have different impurities
Physical Properties of Minerals(can be used to identify the mineral) Luster • Luster refers to the way a mineral reflects light • 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)
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)
Review A naturally occurring solid with a crystal structure • What is a Mineral? • Name 2 things that all minerals have in common? • The mineral group, Silicates, is made up of what two elements? • How are minerals identified? Inorganic, Crystalline Structure, Formed Naturally, Unique Chemical Composition Oxygen and Silicon Color, Luster, Streak, Hardness, Cleavage, Fracture