1. Part 1 – Properties of Minerals Part 2 – Identification of Minerals Part 3 – Mineral Resources

2.  Essential Questions: What are the five defining characteristics of all minerals?  Essential Understandings: A mineral is a naturally occurring, inorganic, solid substance with a definite chemical composition and structure and can be identified based on specific chemical and physical properties.

3. Remember: Now I Can DEFine mineralS 1. Naturally occurring 2. Inorganic 3. Crystalline structure 4. DEFinite chemical composition 5. Solid

4. NATURALLY OCCURRING:INORGANIC:  Minerals occur in nature  A mineral’s atoms are arranged in a specific pattern unique to that mineral  Minerals have never been alive  A mineral is made up of specific chemicals unique to that mineral  Neither a liquid nor a gas CRYSTALLINE STRUCTURE:DEFINITE CHEM COMP: SOLID:

5. Essential Questions:  What are the major elements in rock forming minerals found in Earth’s crust?  How can common minerals be identified based on physical and chemical properties?  What are some examples of major rock forming minerals and ore minerals? Essential Understandings:  There is a difference between rocks and minerals. Most rocks are made of one or more minerals  The major elements found in Earth’s crust are oxygen, silicon, aluminum, and iron. The most abundant group of minerals is the silicates, which contain silicon and oxygen. Some common silicates include feldspar and quartz.  The carbonate group of minerals is composed of the carbonate compound CO 3. Some common carbonates are calcite and dolomite.  The oxide group of minerals is composed of oxygen and a metal. Some common oxides include hematite and magnetite.

6. Essential Knowledge and Skills:  analyze the relationship between the qualities of cleavage, fracture, and hardness and the molecular structure and chemistry of silicates, carbonates, and oxides.  identify minerals by their physical properties, such as hardness, color, luster, and streak.  recognize some major rock-forming minerals such as quartz, feldspar, calcite, and mica.  recognize ore minerals including pyrite, magnetite, hematite, galena, graphite, and sulfur.

7. ELEMENTSMINERALS  The most common elements found in Earth’s crust are oxygen, silicon, aluminum, and iron.  Elements make up minerals  There are about 4000 known minerals  Only about 30 are common  The most common are quartz, feldspar, mica, and calcite.

8.  Minerals and rocks are different!  Quartz, Mica, Feldspar, and Calcite make up most of the rocks found in Earth’s crust  Minerals are the building blocks of rocks  Most rocks are made of one or more minerals

9. SILICATESCARBONATES  Most common group of minerals  Composed of Silicon and Oxygen  Feldspar and Quartz are part of this group  The carbonate group of minerals is composed of the carbonate compound CO 3.  Some common carbonates are calcite and dolomite. OXIDES  The oxide group of minerals is composed of oxygen and a metal.  Some common oxides include hematite and magnetite.

10. Remember!:  Rarely is a mineral identified by a single property.  These properties need to be considered together to correctly identify a mineral.  To be able to identify these and other minerals, we need to look at the properties used to separate and distinguish these minerals.

11.  Visual Properties: Color, Luster, Crystal Shape  Physical Properties: Breakage, Hardness, Specific Gravity, Streak  Special Properties: Effervescence, Magnetism, Fluorescence, Phosphorescence, Double Refraction

12.  Color is the most easily observed mineral property and the least useful!  Many minerals can have a similar color

13.  Many minerals can turn colors due to impurities, or they can change colors in various circumstances.  For example, pure quartz is colorless or white, impurities can make the mineral rose, purple or pink!

14. Luster refers to the way a mineral shines in reflected light. Notice the difference between these two minerals?

15. The mineral on the left has a metallic luster, the one on the right, a nonmetallic luster.

16. There are several terms used to describe nonmetallic luster. Examples could be vitreous, like the quartz on the left, or pearly, like the gypsum on the right.

17. Other terms that might be used include greasy, dull, and earthy. Can you tell which of these has an earthy luster and which has a vitreous luster?

18. Streak of a mineral is the color of its powder when rubbed on an unglazed white tile.

19. The streak is often not the same color as the mineral. A minerals color may vary, but the streak rarely will!

20. The cleavage of a mineral is its tendency to split easily or to separate along flat surfaces. Cleavage can even be observed on tiny mineral grains making it a very useful property!

21. Mica is probably the best example as it splits into thin sheets. It is said to have one perfect cleavage.

22. Feldspar splits readily in two directions, always at or near right angles.

23. Calcite and galena cleave in three directions. They are said to have three good cleavages.

24. Not all minerals show cleavage. Those that don’t break along cleavage surfaces are said to have fracture.

25. The hardness of a mineral is its resistance to being scratched. Diamond is the hardest of all minerals, and talc is the softest.

26. Friedrich Mohs devised a hardness scale. In this scale, ten wellknown minerals are given numbers from one to ten. Lets take a look at the ten minerals used and some of the simple tests.

27. Talc (left) is the softest and has a hardness of 1. A soft pencil lead will scratch talc. Gypsum is a bit harder and has a hardness of 2. A fingernail scratches gypsum.

28. Calcite (left) has a hardness of 3 and a copper penny just scratches it. Fluorite has a hardness of 4 and it can be scratched by an iron or brass nail.

29. Apatite (left) has a hardness of 5 and can be scratched by a steel knife blade. Feldspar has a hardness of 6 and it will scratch a window glass.

30. Quartz (left), with a hardness of 7, is the hardest of the common minerals. It easily scratches hard glass and steel. Topaz has a hardness of 8 and will scratch quartz.

31. Corundum (left) has a hardness of 9. Corundum will scratch topaz. Diamond with its hardness of 10 can easily scratch the rest of the minerals.

32. Crystal shape can be a useful property to identify minerals if the minerals have had the time and space to form crystals. Most mineral grains that are found in rocks, lack the room to grow.

33. Specific gravity tells you how many times as dense as water the mineral is. Pure gold can have a specific gravity as high as 19.3!

34. Calcite is calcium carbonate, CaCO 3. If a drop of weak hydrochloric acid is placed on calcite, the acid bubbles as carbon dioxide is released.

35. MALLEABLE OR DUCTILEMAGNETIC  Minerals that can be hammered thin or shaped are said to show these properties.  Examples: Gold, Silver, Platinum  Some minerals that contain Iron, are magnetic and can be picked up by a magnet.  Example: Magnetite

36. FLUORESCENCERADIOACTIVE  This is the state of glowing while under a ultraviolet light.  Some minerals even glow once the light is turned off!  Some minerals, such as this uraninite, are radioactive.  They give off subatomic particles that will activate a Geiger counter.

37.  Halite (rock salt) can be identified by its taste.

38. Essential Questions:  How are minerals important to human civilization? Essential Understandings:  Minerals are important to human wealth and welfare.

39.  We use minerals everyday! Talc is used in fragrances, powder, ceramics, paint Halite is used as seasoning and food preservation Sulfur is used in fertilizer Mica is used as an electronic insulator Diamonds, rubies, sapphires, and other gemstones are used in jewelry Graphite is used in pencils Fluorite is used as a source of fluoride in toothpaste

40.  At one time or another, over 50 minerals have been mined in Virginia  This has contributed greatly to the state’s economy but also sometimes caused adverse impacts on the public’s health and safety, and the environment.  Gold, copper, gypsum and kyanite have all been mined in Virginia