Minerals UNIT 2 STANDARDS: STATE OBJECTIVES: NCES 2.1.1, 2.1.3, LESSON 2

Lesson Objectives By the end of the lesson, you will have learned: How minerals form Which minerals are the most common in the crust Which properties are used to identify minerals Why some minerals are ores and gems

What is a Mineral? Definition of mineral A naturally occurring inorganic solid with a specific chemical composition and definite crystalline structure. Over 3,000 known minerals in the crust

Components of a Mineral Naturally occurring inorganic The mineral is formed in nature, not man-made Inorganic means they are not alive nor have ever been alive Graphite = yes Sugar = no

Crystals are solids Specific composition Crystals are solids Table Salt is sodium chloride, NaCl Definite shape and definite volume

Definite Crystalline Structure Crystal Basic crystalline systems A solid in which the atoms are arranged in repeating patterns. Cubic, Tetragonal, Hexagonal, Orthorhombic

Where do minerals originate? Minerals can come from cooling magma. Minerals can from from solution As the magma cools, beneath the surface, the atoms begin to align in shapes and form crystal structures. As large volumes of water evaporate, crystals can grow as the solution thickens. (String candy)

Common Elements in the Earth’s Crust

Common Mineral Groups Silicates Oxygen is the most abundant element in the crust followed by silicon. Silicates have 1 silicon surrounded by 4 oxygen atoms. From tetrahedron shapes. Account for 96% of minerals in crust

Common Silicates Quartz Feldspar Olivine Mica

Common Carbonates Carbonate Limestone (chalk) Marble Metal combines with a carbonate ion (CO 3 )

Common Oxides Oxides Examples Iron oxide (rust) Silver oxide (tarnish) Copper oxide (patina) Metal ion and Oxygen

Other Mineral Groups Sulfides Sulfates Halides Native Elements Metal + Sulfur Metal + Sulfate Metal + Halide (VIIA) Metals themselves Copper Gold Platinum

Classifying Minerals Minerals are classified according to their physical and chemical properties.

Identifying Minerals Minerals are classified by Color Luster Texture Streak Hardness Cleavage Density Conductivity

Mineral Classification Terms Color Luster Texture The color reflected back when placed in white light The amount of “shine” Metallic or non-metallic How it feels Smooth, Rough, Greasy, Soapy, glassy

Mineral Classification Terms Streak Hardness Cleavage The color left behind as rubbed across unglazed porcelain tile. How easily the mineral is scratched. Use the Mohs Hardness Scale Talc (Softest)---Diamond (Hardest) How the mineral breaks off in planes. Even cleavage vs jagged breaks

Mineral Classification Terms Density Conductivity Radioactive Ratio of Mass / volume (g/cm 3 ) Specific to minerals Will it conduct electricity Does is register when using a Geiger counter

Mineral Uses Common uses Ores Gems Computers, cars, TV, cosmetics, paints, medicine The substance mined from the earth to extract a metal or mineral. Valuable minerals prized for their rarity. Emeralds, Rubies, Diamonds

Lesson Quiz: Copy and Answer