Transcript minerals
DSL #27 Identify each statement as either True or False. 1. Fossil fuels formed millions of years ago from decayed plants and animals. 2. Most places have winds strong enough to generate electricity. 3. All minerals are solids, but not all solids are minerals. 4. 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 Mineral Group Characteristics Contain Silicates oxygen & silicon The most abundant group of minerals MICA Examples Quartz Mica Feldspar Quartz Mineral Group Characteristics Make up only 5% of the Non- Earth’s crust Silicates Include some of the most important minerals Silver Examples iron, copper, gold, silver, diamonds, rubies Diamond Gold Copper Iron Ruby 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 nonmetallic 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 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 Cleavage or Fracture? 1. 3. 2. 4. Physical Properties of Minerals (can be used to identify the mineral) Review 1. What is a Mineral? 2. Name 2 things that all minerals have in common? 3. A naturally occurring solid with a crystal structure Inorganic, Crystalline Structure, Formed Naturally, Unique Chemical Composition The mineral group, Silicates, is made up of what two elements? 4. Oxygen and Silicon How are minerals identified? Color, Luster, Streak, Hardness, Cleavage, Fracture