What is the Earth’s Crust made of? Recall that there are 2 Types of Crust! Oceanic Crust Continental Crust 2 Major Differences Thickness (Which is thinner?) Composition (What are they made of?) Even though they have different compositions all of the Earth’s crust is composed of …

sulfur gold Minerals malachite rhodochrosite

MINERALS To be classified as a mineral a substance must meet all of the following characteristics: Naturally Occurring Generally Inorganic (not formed by life processes) Solid Substance Definite Chemical Formula (Composition) Orderly crystalline structure In summary, a mineral is a naturally occurring, inorganic solid that has a definite chemical composition and crystal structure.

Processes that form Minerals Crystallization from magma Precipitation Pressure and temperature Hydrothermal solutions (very hot water with dissolved substances. Figure 12: Bornite (blue and purple) and chalcopyrite (gold) are sulfur minerals that form from thermal solutions.

Mineral Groups Classified based on their composition. 1. Silicates - Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron. This silicon-oxygen tetrahedron provides the framework of every silicate mineral. Quartz is the most common silicate mineral. A typical piece of quartz like this contains millions of silicon-oxygen tetrahedra. **Silicates is the most common mineral group on Earth !!!!!

Silicate structures Single tetrahedron = olivine Single chains = augite Double chains = hornblende Sheets = mica 3D networks = quartz, feldspar

Mineral Groups 2. Carbonates - contain the elements carbon, oxygen, and one or more other metallic elements. Calcite (CaCO3) = limestone rock, marble 3. Oxides - contain oxygen and one or more other elements, usually metals. Rutile (TiO2) (magma cools), corundum (Al2O3) (changes in temperature and pressure), hematite (Fe2O3) = rust (exposure to moisture in the air) The Great Pyramid of Giza. One of the Seven Wonders of the Ancient World, the structure is made entirely from limestone. Rusted bolt

halite Pyrite, fool’s gold (sulfide mineral) Gold, native element 4. Sulfates and Sulfides - contain sulfur. Anhydrite (CaSO4) (mineral rich waters evaporate), pyrite (FeS2) = Fool’s Gold hydrothermal solutions) 5. Halides - contain a halogen ion plus one or more other elements. Halite (NaCl) = table salt (salt water evaporates = precipitation) 6. Native elements - exist in relatively pure form. Gold (Au), Silver (Ag), Copper (Cu), Sulfur (S), Carbon (C) = diamond, graphite (Hydrothermal solutions) Pyrite, fool’s gold (sulfide mineral) halite Gold, native element

Common Uses of Minerals copper electrical wiring, coins gold computer circuitry , UV protection for astronauts magnetite natural magnet halite table salt fluorite toothpaste galena car batteries, iron extraction molybdenite steel and soil additive sulfur matches zeolite water softener diamond drills