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.
Hexagonal Structure: http://www.gemsociety.org/info/igem9.htm