Minerals

Galena

high density mineral that is an ore of lead

Hematite

ore of iron and also used as a pigment

Pyrite

fool's gold; mineral that can strike fire

Talc

soft mineral that is used as talcum powder

Limonite

A type of iron oxide that is yellowish-brown when powdered

Mica

mineral that readily splits into thin, shiny sheets; used for glitter

Calcite

common mineral that is a main component of limestone

Halite

rock salt

Fluorite

Illinois' state mineral that shows variation in color

Quartz

very common mineral that comes in a variety of colors

Potassium Feldspar

common component of igneous rocks

gypsum

widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, drywall and blackboard or sidewalk chalk

hardness

a measure of a mineral's resistance to scratching, often assessed using the Mohs scale.

streak

the color of a mineral's powder when rubbed on a surface

specific gravity

the ratio of the weight of a mineral to the weight of an equal volume of water, used to help identify minerals.

luster

the way light interacts with the surface of a mineral, describing its appearance.

cleavage

the tendency of a mineral to break along flat planes of weakness, resulting in smooth surfaces.

fracture

the way a mineral breaks unevenly or unpredictably, resulting in irregular surfaces.