Minerals

What is a Mineral? Naturally-formed solid substance with a crystal structure Pyromorphite

What do all minerals have in common? 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

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)

Mineral Identification There are six different test that are used to identify what type of mineral a mineral is. Color Luster Streak Hardness Cleavage/Fracture Special Properties

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 light 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

Cleavage or Fracture? 1. 4. 3. 2.

Physical Properties of Minerals Density: how much matter is in a given amount of space. see if the object floats or sinks in water. Water’s density is 1: If it floats = density is less than 1 If it sinks= density is more than 1 *THIS IS CALLED SPECIFIC GRAVITY

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?

Quick Hardness Test Penny, pencil, fingernail 1. Use your fingernail to try to scratch the graphite tip of your pencil 2. Now try to scratch the penny with your fingernail 3. Rank these 3 materials in order from softest to hardest on an index card. Explain why you ranked them this way.

Watch Classifying Minerals Clip