1. MINERALS

2. BIG Idea: Minerals are an integral part of daily life.
What exactly does ‘integral’ mean?

4. A mineral is a… naturally occurring, inorganic, solid
with a definite chemical composition and structure.

5. There are over 3,000 known minerals on Earth
Fewer than 20 of these are considered “common”

6. Scientists ask FOUR (4) questions…
If the answer is YES to ALL 4, then the substance IS a mineral!

7. 1. Does it occur naturally?
Is it found in nature?
Brass cannot be found in nature
Brass is a combination (man-made mixture) of zinc and copper
Brass is NOT a mineral

8. 2. Is it inorganic? Organic comes from living things
Inorganic never lived
Minerals must be INORGANIC
Coal is made of plants - it is organic and NOT a mineral

9. 3. Is it a SOLID in crystalline form?
Oil is natural…but it is a liquid
Minerals must be SOLID
Why else would oil not pass the test?

10. 4. Does it have a definite chemical composition?
Elements in minerals are combined in a definite amount, with a specific crystalline pattern
Why is concrete NOT a mineral?

11. Rocks vs. Minerals Rocks are made up of minerals
Rocks can be made of one or more minerals

12. Major Rock-Forming Minerals:
Quartz
Feldspar
Calcite
Mica

13. Rock-forming minerals make up the Earth’s crust…

14. What are the most abundant elements in the Earth’s crust (by mass)?

15. Oxygen (O) - 46%
and
Silicon (Si) - 28%

17. Composition of the Earth’s Crust
Minerals are composed of elements and compounds, and are classified into TWO (2) main groups (based on chemical composition):
Silicates
Contain silicon (Si) and oxygen (O)
96% of Earth’s crust
Nonsilicates
Do not contain silicon

18. Crystal Structure The internal arrangement of atoms Determines:
Crystal form
Breaking pattern
Hardness

19. Diamonds and Graphite are both made of carbon
What makes them look so different?

20. …the internal arrangement of atoms, and the bonds between them…

21. Diamond (a) vs. Graphite (b)

22. Do you know what we use graphite for?

24. How can we identify minerals?
Based on their physical and chemical properties…

25. 1. COLOR
Why do you think color is not a good way to identify a mineral?

26. These 3 minerals are all samples of QUARTZ:

27. 2. STREAK: the color of a mineral in POWDER form
More reliable than color

28. 3. LUSTER: the way a mineral’s surface reflects light

29. Two (2) Types of LUSTER:
A. Metallic - looks like metal

30. B. Nonmetallic - does not look like metal
Waxy
Glassy
Earthy (dull)
Pearly

31. 4. HARDNESS: the ability of a mineral to resist scratching

32. Mohs Hardness Scale: assigns a number from 1 to 10
10 is the hardest (diamond)
1 is the softest (talc)
Estimate the hardness of a mineral by dragging the mineral on a piece of window glass to see if it scratches it:
--if it does, its hardness is 5.5 or greater
--if it does not, its hardness is less than 5.5

33. 5. CLEAVAGE vs. FRACTURE: the way a mineral breaks
splitting of a mineral along lines or flat surfaces
usually creates smooth surfaces and edges with the same angle

35. FRACTURE:
when a mineral breaks unevenly in a curved or irregular way

36. 6. DENSITY (Specific Gravity)
Each mineral has small range of possible densities.
Good way to help identify minerals. M D V

37. Other Special Properties of Minerals…
1. MAGNETISM: minerals containing iron
Magnetite

38. 2. DOUBLE REFRACTION: bending of light to produce a double image of objects viewed through them
Calcite

39. 3. FLUORESCENCE – ability to glow under UV light
4. PHOSPHORESCENCE – ability to glow after the UV light is taken away

41. 5. SMELL

42. 6. REACTION TO ACID
Calcite
with HCl
(hydrochloric
acid)