1. 3-1 What is a mineral? 3-2 Identifying minerals? ( epsomite)

2. {enrich} What is a Mineral? n More than 4,000 minerals (40-50 new minerals identified each year!) n but only 100 common minerals n about 20 minerals make up most of Earth’s crust n native elements occur in nature in pure form (ex: gold, copper, diamond, sulfur, graphite, silver, and platinum)

3. n Most minerals are COMPOUNDS… (a chemical combination of two or more elements), while rocks are mixtures of minerals (and sometimes organic matter like shells) n Some minerals are elements (like copper, gold and diamonds)

4. {enrich} Classification of minerals n 95% of the earth’s crust is made of silicates (minerals made of silicon and oxygen): ex: quartz SiO 2 ) n sulfide (+ sulfur) ex: cinnabar (HgS) n sulfate (+sulfur & O) n carbonate (C & O) ex: calcite: CaCO 3 n oxide (+oxygen) ex: corundum: Al 2 O 3 n halide –ex: salt

5. Characteristics of ALL minerals: (INSCC) --foldable-- n Inorganic n Natural n Solid n Compound (or element) n Crystal system

6. n Inorganic – never alive – not from something alive – rocks can have organic matter n Naturally occurring – not synthetic or artificial or man- made

7. n Solid – at room temperature n Chemical composition – some single element in pure form (native elements) like copper, diamond, sulfur – most are compounds like quartz (SiO 2 ) and cinnabar (HgS) – rocks are mixtures – Can you read a chemical equation? n Crystal system – repeating pattern with flat sides (called faces) – most are only visible with a microscope

8. 8 ways to test the identify of a mineral n 1--hardness n 2--color n 3--streak color n 4--luster n 5--density n 6--crystal structure n 7--cleavage/fracture n 8--special properties

9. Hardness n how easy is it to scratch the mineral? n Moh’s scale – 1812 by Friedrich Mohs – 1 (talc) - 10 scale (diamond) – common substances: n fingernail=2.5 n penny=3-3.5 n glass=5.5-6 n steel=5-5.5 n streak plate= 6.5-7.5

11. Colors of QUARTZ

12. Two colors n Color – easy but not reliable – color may change over time – some minerals have MANY colors (like quartz)--due to impurities – many minerals have the same color n Streak Color--practice – more reliable than regular color – color of its powder – use streak plate (unglazed tile) – examples: n pyrite=black n gold=golden, yellow

13. n Luster – how a mineral reflects light from its surface – 1. metallic (shiny) – 2. nonmetallic: glassy, dull, earthy, waxy, pearly n Density – mass/volume – remains the same (no matter the specimen size) – also called “heft” – may use “specific gravity” (same as density, but no units)

14. Types of luster

15. n Crystal System – Example: cubic- – Example: hexagonal n Cleavage/Fracture (paper towel demo) – how a mineral BREAKS – 1. Cleavage=smooth break – 2. Fracture=irregular break— rough, jagged, or curved (most minerals have fracture) n quartz=curved, shell-like surface n copper and iron=hacky fracture (forms jagged points)

16. Special Properties n Fluorescence (glow under UV light)-- scheelite n magnetic--magnitite n radioactive--uraninite n fizzes (gives off CO 2 ) in acid– calcite (demo) n Very malleable (easy to shape)--gold n earthy odor--clay n soapy feeling--talc n feels greasy--graphite n double refraction-- optical calcite

17. Special Properties:

19. n A rock is a mixture of _____________. n minerals

20. Mystery mineral game: n Pick a mineral from pp. 800-801 n other classmates must ask yes/no questions to determine the identity of the mystery mineral (like “20 Questions)

21. LAB: What mineral do you have? n Find color and streak color n What is the luster? n Find the hardness (a range) n Find density (use water displacement for volume)—could use “heft” n AFTER 2-4 tests are completed, try to identify the mineral, then... n Bring the mineral to Mrs. McMullan when finished to see if you are correct and to get another mineral to identify.

22. Questions for review n Which of the following definitions best describes a MINERAL? – a. a substance that cannot be separated or broken down into simpler substances by chemical reactions – b. a substance made up of atoms of two or more different elements joined by chemical bonds – c. a naturally formed inorganic solid that has a definite crystalline structure – d. a solid whose atoms, ions, or molecules are arranged in a definite pattern

23. n Minerals that contain one or more elements combined with silicon and oxygen are called _________ {enrich} n silicates n Which mineral can be identified by tasting? n halite (salt) n What is the difference between a mineral and a rock? n Minerals are elements or compounds. n Rocks are mixtures (or minerals).