Lab 2-2: Properties of Minerals

chemical properties

a material's properties that become evident during a chemical reaction

streak

the color of the powder of a mineral which is usually more consistent than normal mineral color

crystal

the individual mineral grains of many rocks

specific gravity

the ratio of the weight of a substance to the weight if an equal volume of water

inorganic

not organic, thus not part of a life form or made by living or former life forms

Why are other mineral properties less useful for identification?

Because the properties can vary with different minerals. They can be deceiving.

Why is color alone not a reliable means of identifying a mineral?

Because the colors of minerals can vary

What mineral is usually identified by using the acid test?

Calcite

What is the distinction between cleavage and fracture?

Cleavage is a mineral's tendency to split easily along planes parallel to the crystals faces and fracture is the appearance where a mineral breaks along, other than cleavage planes

A mineral has a specific gravity of 7.0. What does this mean?

It means the mineral is relatively heavy

List the properties which are most useful in identifying minerals.

Luster, hardness, streak, cleavage and fracture

hardness

the resistance of a mineral to being scratched, the "scratchability" of mineral

fracture

appearance of a mineral surface where it breaks along other than cleavage planes

mineral

naturally occurring, inorganic solids with definite crystalline structures and compositions

cleavage

the tendency of a mineral to split easily along planes parallel to the crystal faces

luster

the way a mineral looks or shines in reflected light

How is the hardness range for a mineral determined?

By performing a series of simple tests such as scratching the mineral with a fingernail, copper penny, steel nail and using the mineral to scratch things like glass, steel, and other minerals (Mohs Hardness Scale)

Why is streak a more reliable property than color in mineral identification?

because streak is more consistent than the color of a mineral