Daily Science

1. Daily Science Last class we talked about the six types of crystal systems. A diagram can be found on page 78 in the book. You and each one of your partners should construct one of the systems using the materials on my desk. Every one at your table should make a different system. If you get an easy system (such as cubic) then you should make another system. Each set of groups should have representations for each system.

2. Identifying Minerals Pg. 17

3. Mineral Identification Geologists rely on simple tests to identify minerals Based on chemical and physical properties Usually a combination of tests

4. Color Sometimes trace elements cause certain characteristic colors Least reliable clue for identification

5. Luster The way a mineral reflects light Described as being either metallic or nonmetallic Differences in luster are caused by difference in chemical compositions

6. Texture How the mineral feels to touch Words used to describe: smooth, rough, ragged, greasy, soapy

7. Streak The color of a mineral when it is broken up and powdered. Rubbed across an unglazed porcelain plate. A minerals streak doesn’t always match its color Streak color is always the same

8. Hardness A measure of how easily a mineral can be scratched Most useful tests Use Mohs hardness scale

9. Cleavage and Fracture Minerals break along planes where atomic bonding is weak Minerals that break easily along a plane are said to have cleavage Minerals that break with rough edges are said to fracture

10. Density and Specific Gravity Specific gravity is the ratio of the weight of a substance to the weight of an equal volume of water. Density reflects atomic mass and structure of a mineral

11. Mineral Uses Ore- a mineral that is useful if it can be mined for a profit Ex. Aluminum (comes from bauxite) Iron (comes from hematite) Use mines to obtain ores Gems are valuable minerals

12. Growing Crystals Use a pipe cleaner to make a shape Boil about 300 mL of water While boiling, add about 50g or borax