1. Minerals Mineral - A naturally occurring inorganic solid with specific chemical composition and a definite crystalline structure. Materials made in a lab are not minerals. Materials that are alive or were once alive are not minerals. No gas or liquid can be considered a mineral. A mineral is a crystal which is arranged in repeating geometric pattern.

2. Formation of Minerals(two ways) 1. Minerals are formed from the cooling of magma. As magma is forced up to the crust it cools and the atoms begin to interact chemically. The rate of cooling determines the size of the mineral. The slower the cooling the larger the crystal

3. 2.Minerals Formed From Solution Minerals can form from a solution that has become saturated. When they reach saturation (supersaturated) they precipitate. Secondly, when minerals dissolve in a solution and then the liquid evaporates. Ex. Gypsum and halite

4. Silicate - tetrahedron

5. Mineral Shapes

6. Mineral Groups 1. Silicates- Makes up 96% of the minerals found in the Earths crust. Are composed of oxygen and silicon and one or more elements. S and O bind in a tetrahedron shape (see fig. page 81) Examples of silicates are Feldspar, quartz, and Mica

8. Feldspar

9. Mica ex of cleavage

10. Carbonates Carbonates- Are minerals composed of one or more metals and a carbonate (CO 3 ). Examples, calcite, dolomite, & rhodochrosite, malachite and azurite see p. 83. Carbonates are found in rocks such as marble and limestone.

11. carbonates malachiteazurite

12. Coquina

13. Limestone

14. Marble

15. Oxides Oxides- Are composed of oxygen and a metal. Examples are Hematite (Fe 2 O 3 ) and magnetite(Fe 3 O 4 ) Uranitite contains uranium which is used to generate nuclear power.  Final note: Minerals formed in a open space look different from minerals that formed in a closed space, see p. 79

16. Hemitite

17. Uraninite Major source of uranium used to generate nuclear energy

18. Magnetite Fe 3 O 4 Hematite and magnitite are good sources of iron

19. Other major mineral groups Sulfides-pyrite Sulfates-anhydrite Halides-halite Native elements-copper metal

20. copper

21. Mineral Identification 1. Color – The presence of trace or compounds within a mineral. Ex. Red Jasper Quartz has traces of iron oxides. Ex. Milky cloudy Quartz could be bubbles of gas or liquid trapped in the mineral.

22. 2. Luster The way a mineral reflects light. Luster can be described as metallic or non-metallic. EX. Silver, gold, copper, and galena are metallic. Other luster descriptions are: Dull, pearly, waxy, or silky.

23. 3. Texture- Is how a mineral feels to the touch. Descriptive words used: Smooth, rough, ragged, greasy, soapy, or glassy.

24. 4. Streak Certain minerals leave a streak of color when run across an unglazed porcelain tile. The streak is not always the same color as the mineral. Ex. Pyrite is a gold color but leaves a greenish black streak. No matter how much a mineral is weathered or which color it is the streak is always the same. Streak can only be used on minerals softer than porcelain.

25. 5. Hardness Measure how easily a mineral can be scratched. Fredrick Moh developed a scale in which the hardness of a mineral can be compared to the hardness of ten known minerals this is known as Moh’s Scale. See on page 86 Table 4-3.

26. Moh’s Scale

27. 6. Fracture and cleavage Atomic arrangement determines how minerals will break. Minerals break along planes where atomic bonding is weak. Ex. Mica is said to have cleavage because it breaks in flat planes. Ex. Obsidian breaks with a rough or jagged edge and is said to fracture.

28. fracture cleavage

29. 7. Density Density Is the atomic mass Is expressed as ratio of mass divided by its volume. D=m/V Geologist use Specific Gravity to measure Density which is the ratio of weight of a substance to an equal amount of water.

30. Special Properties Island spar a type of calcite, causes light to bend as it passes through the mineral. As you look through it, you will see double images. This is known as double refraction, zircon exhibits this special property as well. Calcite (CaCO 3 ) also fizzes when it comes in contact with Hydrochloric acid (HCL). CaCO 3 + 2HCL  CaCl 2 + H 2 O + CO 2

31. Other special properties….. Magnetism ex. Magnetite Distinctive rotten-egg odor when streaked on a plate ex. Sphalerite as a result of the presence of sulfide in the mineral.

32. Ore A mineral is an ore if it contains a useful substance that can be mined for a profit. Ex. gold, silver, titanium, & aluminum

33. Gem Valuable minerals that are prized for their beauty and rarity. Ex. ruby, emerald (more valuable than diamonds ), diamond, satfire.

34. Trace elements Found in some gems. Ex. Amethyst contains trace element which give the gem a lovely purple color. Sapphires contain trace amounts of cobalt or titanium.

35. Mineral Uses Computers Cars Televisions Desks Roads Medicines Building Jewelry Beds Paints Sports equipment