Mineral Identification Chapter 2.3 Are identified by their key characteristics Are identified by their key characteristics

1. Color 1. Color Not the best way to identify minerals. Color can change if small amounts of different elements are added.

2. Luster Describes how light reflects off the surface Metallic Luster Non-metallic Luster

3. Mineral Hardness Ability to scratch another mineral Two Scales Used: Mohs scale Uses Minerals Field scale Uses Objects

Moh’s Scale of Hardness

Field Scale Item Hardness Item Hardness Fingernail 2½ Fingernail 2½ Copper penny 3 Copper penny 3 Glass 5½ Glass 5½ Steel file 6½ Steel file 6½ Streak plate 6½ Streak plate 6½ (floor tile) (floor tile)

4. Streak Color of the powder when rubbed on a “streak plate” Color of the powder when rubbed on a “streak plate” Color varies streak does not. Color varies streak does not. Can be colorless Can be colorless

5. Crystal Shape (Form) External structure due to internal arrangement of the atoms External structure due to internal arrangement of the atoms

6. Cleavage & Fracture How minerals break. How minerals break. Cleavage –breaking along flat surfaces (Ex. Halite) Cleavage –breaking along flat surfaces (Ex. Halite) Fracture – breaking into rough/jagged surfaces. (Ex. Quartz) Fracture – breaking into rough/jagged surfaces. (Ex. Quartz)

7. Density Mass/Volume Mass/Volume Regardless of the size the density of a mineral should be the same. Regardless of the size the density of a mineral should be the same.

Special Characteristics-- the “Acid Test” Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO 2 gas) Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO 2 gas)

Special Characteristics-- Fluorescence Some minerals will glow when placed under short- wave or long-wave ultraviolet rays

Special Characteristics-- Salty Taste Example: Halite Example: Halite DO NOT TASTE YOUR MINERALS! DO NOT TASTE YOUR MINERALS!

Special Characteristics-- Magnetism Many iron minerals will produce an invisible magnetic force field

Two Types of Minerals 1. Non-Metals 1. Non-Metals Dull Surface Dull Surface Poor conductors of electricity Poor conductors of electricity Not easily shaped without breaking Not easily shaped without breaking Includes certain gemstones (rubies, emeralds, topaz) Includes certain gemstones (rubies, emeralds, topaz)

2. Metals Ductile – stretched and pulled into wires (ex. Copper) Ductile – stretched and pulled into wires (ex. Copper)

2. Metals Malleable – hammered and shaped with out breaking. (example- sheet of aluminum). Malleable – hammered and shaped with out breaking. (example- sheet of aluminum).

2. Metals Conductors – electricity and heat can flow through a material easily. Conductors – electricity and heat can flow through a material easily.

Mineral Identification Lab Please listen for Instructions Please listen for Instructions