What is a Mineral? Naturally-formed solid substance with a crystal structure Pyromorphite
How do minerals form? Cooling of magma (hot, liquid rock and minerals inside the earth Fast Cooling = No Crystals (mineraloids) Medium Cooling = small crystals Slow Cooling = large crystals
What do all minerals have in common? Are formed by natural processes. Are formed by natural processes. Are NOT alive and NEVER were alive. Are NOT alive and NEVER were alive. Have a definite volume and shape. Have a definite volume and shape. Are elements or compounds with a unique chemical makeup. 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). Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL).
Name five properties (or clues) that scientists use to identify minerals. Color Luster Streak Hardness Cleavage and fracture
Color:
Why is color not a good property to use to identify a mineral? Many minerals have the same color. slate limestone
Which property means the way a mineral reflects light from its surface?
What words can be used to describe a mineral’s luster? Metallic Greasy Waxy Dull
Luster: How minerals reflect light Non- metallic Metallic
Streak: The powdered form of a mineral
Streak…can help identify quartz
Hardness: How easily a mineral scratches other materials is tested by Mohs Scale of Hardness. Scale from 1 (softest) to 10 (hardest)
What are three testers that can be used to determine a mineral’s hardness? fingernail, penny, nail
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? *Cleavage *Fracture
Other Properties Smell or taste Smell or taste Reaction to acid Reaction to acid Striations Striations Attraction to magnets Attraction to magnets Bending of light Bending of light