1. Mineral Groups

2. You can find minerals almost anywhere. Many minerals are abundant and many have important uses Minerals are grouped into families according to the elements in them

3. Silicates Ninety percent of the minerals in Earth’s crust are silicates

4. Quartz Chemical formula - silicon dioxide Colorless or white Hardness of 7 Used in watch movements, prisms, lenses and jewelry

5. Feldspars Contains silicon, oxygen and aluminum Makes up 60% of the Earth’s crust Hardness of 6 Cleavage (quartz doesn’t have cleavage) Classified into 2 groups: potassium (pink) and sodium (white or gray) feldspars Used to make paint

6. Pyroxene Contains silicon, oxygen, iron and magnesium Cleavage at 90 degrees Hardness of 5-6

7. Mica Very soft silicates (2.5) Cleaves into flat sheets Muscovite – white, contains aluminum Biotite – black, contains iron Rock-forming mineral

8. Carbonates All members of this family contain carbon and oxygen

9. Calcite Most common carbonate mineral (calcium carbonate) Colorless or white Hardness of 3 Three directions of cleavage Reacts with hydrochloric acid

10. Dolomite Oops…….not this Dolomite

11. Dolomite Contains calcium magnesium carbonate Hardness of 3.5 – 4 Cleavage (3 directions) Reacts with hydrochloric acid, but only in powder form

12. Oxides and Sulfides Oxides contain oxygen. Sulfides contain sulfur

13. Hematite Most common iron oxide Uneven fracture Earthy luster, but some samples have a metallic silver luster Hardness of 5-6 Red streak

14. Magnetite Iron oxide Is magnetic Hardness of 5.5-6.5 Because of its magnetic properties, magnetite was used to make the first compass (lodestone)

15. Pyrite Iron sulfide ( a compound containing iron and sulfur) Pale brass to golden yellow Hardness of 6 6 or 12 sided crystals Also known as ‘fools gold’