1. MINERALS
Reese

2. How do they form
Minerals form when molten materials cools and hardens inside the Earth or on the surface.
Sometimes minerals from when solutions with solutes evaporate.

3. MINERALS Occur naturally and are inorganic solids (not alive).
Have crystalline
structure.

4. MINERALS Chemically minerals are elements or compounds.
Example: Gold is an element & a mineral.
Example: NaCl is a compound & a mineral.

5. MINERALS Rocks are made up of two or more minerals.
Example: Limestone is
a rock made up minerals
calcite & aragonite.
Rocks can be minerals but
not all minerals are rocks.
Example: Cu is a mineral
but is not a rock

6. MINERALS
There are about 3,000 minerals on Earth.

7. BARITE

8. CARBON

9. QUARTZ

10. GRAPHITE

11. Copper

12. FLUORITE

13. MINERAL PROPERTIES

14. LUSTER
The way a mineral’s surface reflects light.

15. LUSTER
May vary from one sample to another sample of the same substance.
Two major types of luster:
Metallic
Nonmetallic

16. Metallic Luster

17. Nonmetallic luster
Earthy Luster
Glassy

18. Nonmetallic Pearly Luster

19. COLOR
Not very useful for identifying minerals whose color vary with the sample.
Example: the colors of minerals quartz & fluorite vary with their samples.
Quartz Fluorite

20. COLOR
Useful only for those minerals which always have the same color or very unique colors.
Example: Malachite– green
azurite----- blue

21. SULFUR

22. Malachite

23. Azurite

24. STREAK Color of a mineral in it powdered form.
Can be obtained by rubbing the mineral across a streak plate-- a piece of unglazed porcelain tile.
Example: hematite always gives a reddish brown streak no matter what type of luster it displays.

25. Streak Examples
Hematite leaves a reddish brown streak.

26. Streak Examples
Pyrite leaves a greenish black streak.

27. HARDNESS Ability of a mineral to resist scratching.
It is tested using the Mohs Hardness Scale.

28. Mohs Hardness Scale
Based on the fact that a harder mineral will scratch a softer one.
Ten minerals are numbered from softest to hardest.
Talc is the softest & has a value of 1.
Diamond, the hardest of all minerals, has a value of 10.

30. DENSITY Useful mineral identification property.
Used to determine the identity and purity of minerals.
Pure mineral density is a constant value.
Density = mass/volume.
Example: gold and pyrite appear similar. Pyrite is often called “fool’s gold”. You can tell the two minerals apart by comparing their densities.
Gold’s density: 19.3 g/cc
Pyrite’s density: 5.01 g/cc