1. Mineral Presentation Talc 11A Iris

2. Properties Name: Talc Color: White, light gray, or other light color Streak: White, colorless Hardness: 1 Transparency: Translucent to opaque Luster: Vitreous Chemical Formula: H 2 Mg 3 (SiO 3 ) 4

3. Talc is sectile, it can be cut with a knife. It is not soluble in water, but it is slightly soluble in dilute mineral acids. The specific gravity of it is about 2.5 to 2.8.

4. Formation serpentine + carbon dioxide → talc + magnesite + water (2 Mg 3 Si 2 O 5 (OH) 4 + 3CO 2 → Mg 3 Si 4 O 10 (OH) 2 + 3 MgCO 3 + 3 H 2 O) dolomite + silica + water → talc + calcite + carbon dioxide (3 CaMg(CO 3 ) 2 + 4 SiO 2 + H 2 O → Mg 3 Si 4 O 10 (OH) 2 + 3 CaCO 3 + 3 CO 2 ) chlorite + quartz → kyanite + talc + water

5. Uses Talc is one of the softest mineral on the earth, even fingernails can scratch it easily. Sometimes we can draw a white line by using talc instead of using chalk.

6. Talc also can be used in the medicine(most in traditional Chinese medicine) It is used to relieve inflammation (clear heat) and detoxify. It is diuretic.

7. Talc is used in many industries such as paper making, plastic, paint and coatings, rubber, food, electric cable, cosmetics, etc. It is used as a cosmetic (talcum powder), as a lubricant, and as filler in paper manufacture. It is used in the basketball to keep the player’s hands dry.

8. Crystal System The crystal system of talc is monoclinic.

9. Bibliography http://en.wikipedia.org/wiki/Talc http://www.minerals.net/mineral/talc.aspx http://geology.com/minerals/talc.shtml

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