Mineral Presentation

Talc

11A Iris

Properties

• Name: Talc• Color: White, light gray, or other light color• Streak: White, colorless• Hardness: 1 • Transparency: Translucent to opaque• Luster: Vitreous• Chemical Formula: H2Mg3(SiO3)4

• 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.

Formation

• serpentine + carbon dioxide → talc + magnesite + water• (2 Mg3Si2O5(OH)4 + 3CO2 → Mg3Si4O10(OH)2 + 3 MgCO3 + 3 H2O)

• dolomite + silica + water → talc + calcite + carbon dioxide• (3 CaMg(CO3)2 + 4 SiO2 + H2O → Mg3Si4O10(OH)2 + 3 CaCO3 + 3 CO2)

• chlorite + quartz → kyanite + talc + water

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.

• 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.

• 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.

Crystal System

• The crystal system of talc is monoclinic.

Bibliography

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

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