1. Mineral Identification
Minerals can be identified by a combination of their physical properties (characteristics).

2. COLOR
Some minerals come in more than one color. Ex. Quartz

3. Some different minerals have similar colors. Ex
Some different minerals have similar colors. Ex. Fluorite and Amethyst Quartz

4. LUSTER Definition: How a mineral reflects light.
Luster can be divided into two categories:
A. Metallic- Shines like a metal
1. metallic shiny – ex. Graphite and Galena

5. Metallic Luster
2. Metallic Dull- looks more like a rusty nail

6. LUSTER NON-METALLIC- doesn’t shine like a metal
Glassy luster ex. Quartz

7. Non-metallic luster
2. Pearly- shine like a pearl ex. Talc

8. Non-metallic luster
3. Silky luster- shines like corn silk
ex. Gypsum

9. Non-metallic Luster 4. Waxy luster- shines like candle wax
ex. Some Quartz and some Halite

10. Non-metallic Luster
5. Earthy Luster- “shines” like dirt
ex. Bauxite

11. Non-metallic luster
6. Resinous Luster- shines like sticky honey or amber ex. Sphalerite

12. One kind of mineral can have two different forms and so it may have two types of luster.
ex. Hematite- it may be Specular Hematite which is metallic-shiny, or it can look metallic-dull

13. Mini Lab
1. Get a tray -divide the minerals in to two groups: metallic and nonmetallic
2. Divide the metallic minerals in to two groups: shiny and dull metallic
3. Group the nonmetallic minerals by glassy, pearly, silky, waxy, earthy, and resinous luster

14. STREAK
Streak-color of a mineral’s powder when scratched on an unglazed porcelain tile called a streak plate
Not all minerals leave a streak!

15. HARDNESS Hardness- a mineral’s resistance to being scratched
Friedrich Mohs invented Mohs Scale of Hardness
Diamond- hardest mineral; Talc softest mineral

16. MOHS SCALE OF HARDNESS Diamond – the hardest mineral 9 Corundum
8 Topaz
7 Quartz
6 Orthoclase (Feldspar)
5 Apatite
4 Fluorite
3 Calcite
2 Gypsum
1 Talc – represents the softest mineral

17. MNEMONIC DEVICE
To learn Mohs Scale of Hardness, memorize the following sentence:
“To Get Candy From Aunt Fanny, Quit Teasing Cousin Danny.”
Did you notice that the first letter of each word in the sentence corresponds to the first letter of each word in Mohs Scale? This is a mnemonic device (memory aid)

18. MOHS SCALE OF HARDNESS Talc (softest) To Gypsum Get Calcite Candy
Fluorite From
Apatite Aunt
Feldspar Fanny
Quartz Quit
Topaz Teasing
Corundum Cousin
Diamond (Hardest) Danny

19. COMMON OBJECTS TO HELP TEST MINERAL HARDNESS
The following objects can be used to help determine the hardness of a mineral:
Fingernail –Hardness of 2.5
Copper Penny- H: 3.1
Iron Nail – H: 4.5
Glass Plate – H: 5.5
Steel File – H: 6.5
Streak Plate – H: 7.0

20. Mini Lab
Divide the minerals into metallic and nonmetallic luster and check with teacher
Check the streak of the metallic and nonmetallic minerals and tell your teacher what you found out (AHA!!)
Take the nonmetallic minerals and line them up by hardness using tools and the minerals themselves to help you!
Memorize Moh’s Scale for a quiz next week

21. CLEAVAGE
Cleavage- the way a mineral may split easily along flat surfaces

22. Planes of weakness
Ex.) Halite has an atomic structure that forms cubic breakage

23. Geologists use hammers and knives to determine how a mineral breaks

24. Minerals may have very distinctive cleavage
Mica-one direction of perfect cleavage.
Calcite (rhombic) and Galena (cubic)- cleavages in 3 directions.

25. Cleavage can be observed under a microscope in a thin section

26. FRACTURE
Fracture -the way a mineral breaks unevenly, not with smooth, flat surfaces
Examples:
a. Conchoidal fracture -a curved, shell-like pattern, like broken glass; ex. Quartz

27. OTHER FRACTURE PATTERNS
b. Fibrous fracture looks splintery. Ex. Gypsum and Asbestos

28. MORE FRACTURE PATTERNS
c. Irregular or uneven fracture- shows no definite pattern; ex. Hematite and Magnetite

29. CRYSTAL SHAPE Some minerals can be identified by their crystal shape-
a. CUBIC – Ex. Pyrite, Halite, Galena

30. OTHER CRYSTAL SHAPES b. HEXAGONAL- six sided crystals
Ex. Corundum and Quartz

31. MORE CRYSTAL SHAPES
c. RHOMBIC- shaped like a parallelogram; ex. Calcite

32. SPECIAL PROPERTIES OF MINERALS
Some minerals have very distinctive properties that can be used to identify them:
a. Effervescence (acid test) – when HCL (hydrochloric acid) is added to calcium carbonate (CaCO3), it causes bubbling as carbon dioxide (CO2) is released; ex.) Calcite is a mineral that bubbles with acid

33. EFFERVESCENCE- Acid test

34. MORE SPECIAL PROPERTIES
b. Double Refraction- an optical property of some varieties of calcite that gives a double image effect.

35. MORE SPECIAL PROPERTIES
c. Magnetism- minerals with this property are attracted to magnets; ex. Magnetite

36. SPECIAL PROPERTIES CONTINUED
d. Fluorescence- property where the mineral glows under ultra-violet light; ex. Fluorite and some calcites

37. MORE SPECIAL PROPERTIES
e. Radioactivity- minerals that contain radium or uranium can be detected by a Geiger counter. They give off radiation (gamma rays).

38. SPECIFIC GRAVITY
Specific Gravity is the heaviness of a mineral as compared to water. It’s similar to density. Pyrite has a s.g. (or density) of Remember water is 1.0.

39. MORE ABOUT SPECIFIC GRAVITY
Used to compare two similar looking minerals- Pyrite (fools gold) looks like Gold but has a lower specific gravity number

40. WHAT NOW?
It’s time to practice what you have learned about properties of minerals by identifying 15 important minerals. Good luck!
Don’t depend on your partner- there will be a challenging mineral lab test at the end of the unit.