Rocks & Minerals

1. Rocks & Minerals Miss Napolitano & Mrs. Rodriguez Environmental Science

3. Minerals combine to make rocks! • Minerals: naturally occurring, inorganic, solid compounds with a definite crystalline structure & chemical composition • Rocks: Solid mass composed of a combination of minerals or organic compounds Rocks vs. Minerals

4. Produced by nature • Solid • Organic compounds (contain C & H) & are NOT produced by organic processes • Have a definite crystalline structure • Have a definite chemical formula What makes a mineral? Halite - NaCl For every atom of Sodium there is an atom of Chlorine.

5. Diamond • Teeth • Kidney stones • Gold • Pearls • Clay • Zinc • Amber • Sea shells • Mica Mineral or Not?

6. Diamond – Mineral! • Teeth – Not! • Kidney stones – Not! • Gold – Mineral! • Pearls – Not! • Clay – Mineral! • Zinc – Mineral! • Amber – Not! • Sea shells – Not! • Mica – Mineral! Mineral or Not?

7. Minerals can be classified in the following ways: • Hardness • Cleavage/Fracture • Streak • Luster • Color • Specific Gravity • Taste • Magnetism • Light • Chemical Properties Mineral Classification

8. Resistance a mineral has to being scratched • Minerals are scratched against one another • The one that has scratch marks is the softer mineral • Use Moh’s Scale of Mineral Hardness as a guide! Hardness

10. Cleavage: the tendency of a mineral to break along smooth planes • Fracture: the tendency of a mineral to break along curved planes • Think: like tearing paper along perforations Cleavage/Fracture

11. Streak: the color of the mineral in powder form • Mineral is rubbed across a streak plate (porcelain) • Streak plate hardness = ~7 • Some minerals have surprising streak colors! Streak

12. Luster: the quality of reflected light • Classified as either metallic or non-metallic Luster

13. Easiest to notice but not always reliable! • The picture shows different versions of calcite: Color

14. Specific Gravity: mineral density • Weighed in air, then weighed in water Specific Gravity

15. DO NOT PERFORM A TASTE TEST ON ANY UKNOWN MINERALS – SOME ARE TOXIC!! • But, some minerals have unique tastes Taste

16. Magnetism: the ability of a mineral to be attracted by a magnet • Usually indicates if a mineral has a high concentration of iron Magnetism

17. Minerals are classified as opaque, translucent, or transparent • Opaque: no light passes through • Translucent: some light passes through • Transparent: you can see through the mineral Light

18. Transparent minerals can also display double refraction – beams of light separate to display a double image Light – Double Refraction

19. Minerals can display certain chemical properties, such as reaction with acid or reaction with ice Chemical Properties

20. Use this time to take Cornell Notes on classifying minerals! (~5 minutes) • Take out a piece of paper & fold in half (hot dog) – 1 side can be bigger than the other • On smaller side: write main ideas • On larger side: write supporting details • Write down any questions at the bottom/on the back of your paper! Brain Break – Cornell Notes

21. Rocks are classified by how they are formed • 3 main types of rocks: • Igneous • Sedimentary • Metamorphic Rocks

22. Cooled magma from the mantle • BTW: magma = underground, lava = aboveground • Ex: granite Igneous Rocks

23. Composed of pre-existing rocks • General characteristic =stratification (layering) • Due to weathering & erosion • Ex: limestone, coal, gypsum Sedimentary Rocks

24. Rocks that have changed form due to heat, pressure, or fluids • Done without melting • Ex: slate Metamorphic

25. Rocks can change from one form to another! The Rock Cycle