Anne Kohlroser, Mrs. Smith 10/24/13

What is a mineral?

There are five steps to finding a mineral

1. It must be a solid

2. Must be naturally created

3. Inorganic- was never living

4. Have a definite and repeating crystalline structure

5. Have a definite chemical composition

Identifying a mineral

Color- the same mineral can vary in color because of impurities in the mineral.

The color of a ruby varies from bright red to a dark reddish brown

Luster- The way a surface reflects light- it can vary in metals, sub-metals, and nonmetals.

Rubies have a glass like luster, you can see through it like it is glass.

Streak- The color of a mineral in powdered form. Streak is found by rubbing the mineral against a piece of unglazed porcelain.

The streak of a ruby is white,

Cleavage- The tendency of some minerals to break along smooth flat surfaces. Cleavage is found by breaking a mineral and seeing if it breaks flat or into a pattern that can be repeated.

Rubies do not have cleavage.

Fracture- The tendency of some minerals to break unevenly or along curved or irregular surfaces. When a stone with fracture is broken it doesn't break into pieces that are the same.

The fracture of a ruby is uneven

Hardness- A minerals resistance to being scratched. Hardness is found by scratching, or attempting to scratch a mineral on glass.

A rubies hardness rating is a 9. The second hardest rating.

Diaphenity- The ability or inability to see through a stone.

Rubies are transparent to translucent.

Specific gravity or density- The measure of the amount of matter in a given amount of space.

The specific gravity of a ruby is 4. It is a very heavy mineral.

Crystalline Structure- A repeating pattern that is presented through a mineral.

The crystalline structure of a ruby is trigonal or hexagonal.

Special Properties- A special or unique property of a mineral taste, radioactivity, magnetic properties, double refraction, acid test, fluorescence, and etc.

Rubies have double refraction which means that if you hold a piece of paper with a word on it behind a ruby you will see the word twice. The Chromium in rubies also causes them to have fluorescene.


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