MINERALS

Mineral

a naturally occurring solid that can form by inorganic processes and that has a crystal structure and a definite chemical composition

Properties

Characteristics of minerals such as luster, hardness, and cleavage.

color

What is the color of the mineral? Not always useful as many different minerals have the same color.

luster

How is LIGHT reflected off of the mineral? Is it metal? Nonmetal?

hardness

The measure of a mineral's resistance to scratching or abrasion, commonly assessed using the Mohs scale.

Moh’s scale

a scale that ranks minerals based on their hardness from 1 (talc) to 10 (diamond). It is used to determine how resistant a mineral is to scratching.

Streak

The color of the powder produced when a mineral is scraped across a hard surface, often used to help identify minerals.

Cleavage

The way a mineral breaks along specific planes of weakness, resulting in FLAT surfaces.

Fracture

The manner in which a mineral breaks in a random manner, producing UNEVEN or ROUGH surfaces, as opposed to breaking along cleavage planes.

Crystal Form

Ideal shape of the mineral when it grows naturally as a crystal.

Magnetism

A property of certain minerals to be attracted to magnets or exhibit magnetic properties, often due to the presence of iron.

Density

How dense are the particles? Does it sink or float?

Reacts to acid

Refers to a mineral's ability to fizz when exposed to acid.

Geode

a rounded, hollow rock that is lined with mineral crystals

Inorganic

Formed from materials that were NOT part of living things.