1. Minerals

2. Before we begin... Do we eat minerals? yes
Where do these minerals come from? Found in food – taken up by plants or obtained from other organisms, supplements - may have been mined.
Any material in food or tablets was once part of the geosphere.

3. TRUE OR FALSE A mineral is anything solid on Earth.
Some minerals form when water evaporates from Earth’s surface.
The best way to identify a mineral is by color.
An ore is a concentration of minerals that contains only iron.
Gemstone and ore deposits are evenly distributed in the world.
An ore is a body of rock that contains a high concentration of a desired substance.

4. Mono Lake A freshwater lake with higher-than-average salinity.
Streams feeding the lake were diverted to provide drinking water.
As a result, the lake has become three times as salty as the ocean.
Why don’t most other lakes have towers like these?

5. MINERALS
A mineral is a naturally occurring, inorganic solid with a definite chemical composition and an orderly arrangement of atoms or ions. A rock is a naturally occurring aggregate of minerals.
What substances containing minerals do you use throughout the day?
Why are so many minerals used in everyday items?

6. Minerals There are about 3000 known minerals
Minerals are made of elements (either a single element or a combination of elements)
Examples of Minerals
Gold: a mineral made of one element (gold…Au)
Calcite: a mineral made of 3 elements (calcium, carbon, and oxygen…CaCO3)
calcite
gold

7. Scientific Requirements for a Substance to be a Mineral
Must be naturally occurring (they must occur in nature)
Must be inorganic (not made of living things)
Must be crystalline (have a crystal structure – liquids solidify)
Must be solid (minerals are not gases and liquids)
Must have definite physical and chemical properties

8. Mineral distribution (naturally occurring) mrdata.usgs.gov

9. HOW TO FORM A MINERAL
Cool solutions – ex. Rain dissolves minerals in rocks and in soil, water evaporates – leaves behind minerals – (similar to Mono Lake)
Hot Solutions – water on earth’s surface flows into deep and hot environments – hot solution dissolves large quantities of minerals to form new ones
Magma (molten rock – below, lava – above) – as lava cools, minerals form
Changes in Minerals – minerals that move to regions of less density and lower temp can destabilize minerals – break down – new ones form

10. COMMON MINERALS (ROCK – FORMING!)
Silicates – contain silicon and oxygen in its crystal structure (90% of Earth) – ex. quartz
Nonsilicates do not contain silicon – ex. salt vs

11. COOLING DOWN + FORMATION
When a mineral quickly cools, the crystals are tiny because they have had less time to grow.
When a mineral slowly cools, crystals are bigger.
Scientists can infer the internal arrangement of atoms and ions from the shape of the mineral

12. CRYSTALS
A solid of a chemical substance with a regular, repeating pattern

13. How do we identify minerals?
By color: a red mineral is most likely not gold (which is a shiny gold color) or biotite (which is a black color)
By luster: the luster of a mineral describes how shiny it looks (silver has a metallic luster and pure quartz has a glassy luster)
By streak color: What color is the streak when a mineral is rubbed on a porcelain plate?
By hardness: How hard is the mineral? (The Mohs hardness scale uses numbers to describe hardness)

14. MINERAL BREAKS / DENSITY / SPECIAL PROPERTIES
Breaking Minerals
- smooth, flat breaks? Cleavage
- uneven breaks? Fracture
Density – can differ despite similar size
Special Properties – touch, smells, reactions to other substances, magnetic

15. Mohs Mineral Hardness Scale
1) Talc
2) Gypsum
3) Calcite
4) Flourite
5) Apatite
6) Feldspar
7) Quartz
8) Topaz
9) Corundum
10) Diamond
Softest 1 2 3 4 5 6 7 8 9 10
Hardest

16. Do not write all of this down
Mohs Scale is based on the fact that a harder material will scratch a softer one. By using a simple scratch test, you can determine the relative hardness of an unknown mineral.
How to Perform the Test
Select a fresh, clean surface on the specimen to be tested. Hold the specimen firmly and attempt to scratch it with the point of an object of known hardness...
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17. Mohs test – continued... Do not write all of this down
Press the point of the crystal firmly against the surface of the unidentified specimen. If the "tool” is harder, you should feel a definite "bite" into the surface of the specimen. Look for an etched line. It is a good idea to rub the observed line with your finger to ensure that it is actually etched into the surface of the specimen. If there is any question about the result of the test, repeat it being sure to use a sharp point and a fresh surface.
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18. “Tools” for testing the hardness of a material
Your fingernail has a hardness of 2.5. If you can scratch the surface of an unknown specimen with it, you will immediately know that its hardness is less than 2.5. In other words, it is slightly harder than gypsum (H=2) but softer than calcite (H=3).
A penny has a hardness of slightly harder than your fingernail. So, if you can't scratch the specimen with your fingernail (H=2.5), but a penny does the job, you immediately know that it is at least as hard as calcite (H=3).
The steel blade of the average knife usually has a hardness of about 5.5. If a penny does not scratch your unknown specimen but the knife blade does, then you can correctly conclude that it is harder than calcite (H=3) but softer than orthoclase (H=6).
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19. MOHS