<p> Minerals</p><p>Q. What is a mineral</p><p>A. Any substance that meets the following:</p><p>1. Must be a solid</p><p>2. Must be inorganic</p><p>3. Must be naturally occurring</p><p>4. Must have a definite chemical composition (chemical formula) Facts  there are more than 2,000 kinds of minerals, but fewer than 20 are common minerals that form rock  10 minerals make up 90% of the earth’s crust Ex. Quartz, feldspar, mica, calcite</p><p>Two Main Groups 1) Silicates –they contain atoms of silicon (Si) and oxygen. Forms a tetrahedron (see drawing) Many contain one or more kind of atom Ex. Feldspar – silicon and oxygen with (K) – potassium</p><p>*96% of the crust is made of silicates</p><p>2) Non-silicates – six group A. Native elements – One type of atom</p><p>EX. Gold -Au B. Halides – K, Na, or Ca – cation with a Cl or F – anion</p><p>EX. Halite NaCl</p><p>C. Sulfides - contains S atom</p><p>EX. Pyrite FeS2 D. Carbonates – contains CO3 as part of the compound</p><p>EX. Calcite CaCO3</p><p>E. Sulfates – contains SO4 as part of the compound Gypsum – CaSO4 F. Oxides - contains O atom except for silicates, carbonates, and sulfates</p><p>EX. Hematite Fe2O3</p>