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Unit 2- Minerals, Rocks, Soils and Weathering

Unit 2- Minerals, Rocks, Soils and Weathering. Identifying Minerals. How are Minerals Identified?. Minerals can be identified by physical properties. - some can be seen by looking at the mineral - some can be observed by testing the mineral. Color.

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Unit 2- Minerals, Rocks, Soils and Weathering

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  1. Unit 2- Minerals, Rocks, Soils and Weathering Identifying Minerals

  2. How are Minerals Identified? Minerals can be identified by physical properties. - some can be seen by looking at the mineral - some can be observed by testing the mineral

  3. Color • Only used with certain minerals • example: malachite is green • sulfur is yellow • Many minerals such as quartz • come in many colors. For this • reason color is not a good way • to identify minerals.

  4. Luster- how a mineral reflects light from its surface. • Two types • metallic - when a mineral looks • like a metal, regardless of its • color. • non-metallic - when the • mineral does not reflect • light like a metal

  5. Metallic (bright, reflective) Submetallic dull, reflective

  6. Nonmetallic vitreous (glassy, brilliant) resinous (plastic) waxy (greasy, oily) pearly (creamy) silky (fibrous) earthy (rough, dull)

  7. Streak

  8. Streak is always the same for the same mineral. • To find streak, rub the mineral on unglazed porcelain called the streak plate. • The color of the powder is not always the same as the color of the mineral.

  9. Cleavage is when a mineral breaks along planes of weakness. Flat smooth surfaces usually show planes of cleavage.

  10. Example: calcite

  11. Fracture iswhen a mineral does not break along a plane of weakness. Conchoidal fracture is a curved shell shaped break (like on arrow heads)

  12. Example:Rose Quartz

  13. Hardness The ability of a mineral to resist being scratched. • Uses 10 minerals, arranged in order of increasing hardness • Hardness refers to the ability of a mineral to SCRATCH something else. A mineral can only scratch something else if it has an equal or higher HARDNESS RATING than the object to be scratched.

  14. Mohs hardness Scale goes from 1-10 • Finger nail = 2 • Copper wire or penny = 3 • Pocket knife = 5 • Window glass = 6 • Steel file = 7 • Diamond= 10

  15. Density Density is the measure of how much matter is in a given amount of space. D=m/v Wood 1.05 g/cm3 Aluminum 2.69 g/cm3

  16. Specific gravity • Ratio or comparison of the density of a mineral to the density of water. There are no units since they cancel out each other. Ex. Pyrite is 5 times heavier than water

  17. Gold is considerably more dense than pyrite. The density of pyrite (FeS2) is 5.02 grams per cc, and the density of gold is 19.3 grams per cc, meaning that gold is 19.3/5.02 or 3.84 times as dense as pyrite.

  18. Special Properties of Minerals • Magnetite (lodestone)-made of iron • and oxygen is naturally magnetic • Fluorite-Displays Fluorescence, glows under UV light • Halite-(table salt) has a special taste • Sulfur-smells • Calcite-fizzes when hydrochloric acid is • added to it displaying a chemical reaction • Calcite-displays a double image related to its optical • properties • Some minerals-are radioactive if they contain • uranium and radium

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