1. All in the Mineral Family Chapter 3: Minerals

2. Elementally Speaking  Most minerals are made of 2 or more elements  8 elements are in greatest abundance in the Earth’s crust, with silicon and oxygen found in most minerals  8 abundant elements are: 1. Silicon (Si) 2. Oxygen (O) 3. Aluminum (Al) 4. Iron (Fe) 5. Calcium (Ca) 6. Sodium (Na) 7. Potassium (K) 8. Magnesium (Mg)

3. Family Time  When studying the chemical formulas for minerals, we look at 3 different groups: silicates, non- silicates, and native elements  Silicates are the largest group and native elements are the smallest group

4. The Silicates  Also called the “rock formers” because they make up most of the rocks that we see  All members of this family contain SILICON and OXYGEN (SiO)  Most common members are quartz (SiO 2 ) and feldspar (KAlSi 3 O 8 ) Rose Quartz Feldspar

5. The Non-Silicates  This family contains anything that is NOT a silicate, with no SiO ion in its chemical formula  Chemical formula is expressed as a METAL + ION  Broken down into 4 sub- families: carbonates, oxides, sulfates, and sulfides Magnetite

6. Carbonates and Oxides  In members of the carbonate family, you are looking for the CO 3 ion  An example is the mineral calcite, which is CaCO 3  Members of the oxide family have a metal + oxygen ion as its chemical formula  An example is the mineral hematite, which is Fe 2 O 3 Calcite Hematite

7. Sulfates and Sulfides  In the sulfate family, you are looking for the SO 4 ion  An example is the mineral gypsum, which is CaSO4 + 2H2O  In the sulfide family, you are looking for a metal + sulfur ion  An example is the mineral galena, which is PbS Gypsum Galena

8. Native Elements  This is the smallest group of elements  Consists of elements that exist by themselves in nature  Examples are gold (Au), silver (Ag), copper (Cu), and diamond & graphite (C) Copper

9. Crystallography….What is it?  Mineralogists study the arrangement of the interlocking crystals in minerals  Crystals are created because of the repeating pattern of atoms  6 main crystal shapes: cubic, tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic

10. Examples of Crystal Shapes