1. Minerals

2. What is a Mineral? Solid Naturally Occurring Inorganic
Definite Crystal Structure
Definite Chemical Formula

3. Minerals are Identified by their Physical and Chemical Properties
Crystal Structure
Color
Luster
Streak
Cleavage and Fracture
Reactions with Acid
Other Special Properties
Hardness
Specific Gravity

4. Crystal Shape
the crystal shape results from the atomic arrangement into geometric patterns when the mineral forms
Cubic

5. Tetragon

6. Monoclinic

7. Triclinic

8. Orthorhombic

9. Hexagon

10. Color
Usually the first and most easily observed but the least accurate property
-one mineral may come in many colors
-different minerals are the same color
-color changes due to impurities or exposure to air or radiation
ROSE QUARTZ
QUARTZ
SMOKY QUARTZ

11. Color
-different minerals are the same color

12. Luster appearance of a mineral’s surface as it reflects light
Metallic – look like shiny car
Nonmetallic
Glassy shine
Muted shine
Dull shine

13. Streak
Color of the mineral’s powder as determined by rubbing the mineral on a piece of unglazed porcelain called a streak plate

14. Cleavage and Fracture
Minerals break along lines of weakness in their crystal structure
Cleavage occurs when a mineral splits or cracks along flat planes
Fracture occurs when a mineral breaks at random lines

15. Reactions with Acid
Minerals in the Carbonate Family (-CO3) react chemically with acid to produce carbon dioxide gas
Reaction creates bubbles of gas and the mineral appears to fizz

16. Hardness Mohs Scale Mineral hardness was in use as long ago as 300 BC
Current system was invented by German scientist in 1812
Based on a mineral’s resistance to being scratched

17. Minerals in Mohs Scale
softest
hardest

18. Mohs scale of mineral hardness - Wikipedia, the free encyclopedia
Absolute Hardness
Mohs scale of mineral hardness - Wikipedia, the free encyclopedia

19. Hardness In the field, common objects are used to determine hardness.
>2 fingernail
3 penny
~5 steel of a pocket knife
5.5 glass
6.6 steel of a file
7 quartz crystal
emery

20. Brinell Hardness Test
developed by Swiss engineer Johan August Brinell in 1900 for metals
evaluates strength by using a tiny cannon to shoot a small steel ball into the sample and mathematically analyzing the results
1906 a similar wood hardness test was developed

21. Brinell Cannon

22. Modern Versions of the Brinell Hardness Tester

23. Sapphire is related to Corundum, #9 on Mohs Scale
Apple is trying to develop sapphire screens for iPhones.

24. Special Properties Magnetism Taste Smell Fluorescence Phosphorescence
Refraction
Electrical
Radioactive

25. Specific Gravity
Similar to density, which is the amount of matter in a given space (Mass/Volume)
Compares density of the sample with the density of water
Determined by dividing the mass of the sample by an equal volume of water
<3 is nonmetal, >5 is metallic
Tells you how many times more dense than water the mineral is