Minerals Mineral Mineral Formation A naturally formed, inorganic solid that has a definite crystalline structure. – Naturally formed – not made by people – Inorganic – made from non-living things – Solid – definite shape and volume – Crystalline structure – repeated inner structure that helps shape the mineral All minerals are made from elements Most minerals are compounds – two or more elements that go through a chemical change

Crystal Structure Silicates Each mineral has a definite crystalline shape or repeating inner pattern of atoms – All minerals can be classified according to their crystal structure Minerals that contain a combination of the elements silicon and oxygen – Make up 90% of the Earth’s crust – Examples: quartz, Mica, Feldspar

Nonsilicates Mineral Identification Minerals that do not contain a combination of oxygen and silicon Often contain the elements such as Carbon, Fluorine, Sulfur, and Oxygen Examples: Copper, Calcite, Fluorite, Gypsum and Galena Minerals can be identified by their physical properties such as color, luster, streak, hardness, and fracture

Color Luster Streak Minerals come in a variety of colors – Colors can be influenced by impurities The way a surface reflects light – Minerals can have a metallic or shiny luster – Minerals can have a nonmetallic or dull luster Color of a mineral in powdered form – True color of the mineral

Cleavage / Fracture Hardness Cleavage, tendency to break along smooth, flat surfaces Fracture, tendency to break along unevenly curved or irregular surfaces Resistance to being scratched – Minerals are rated 1 to 10 – 10 is the hardest and 1 is the softest