GEOL 101 1nd Edition Lecture 5 Outline of Last Lecture I Dynamic Earth II Minerals as Building Blocks III Physical Properties of Minerals Outline of Current Lecture I Classification of Minerals II Classification of Silicate Minerals III Classification of Non silicates IV Mineral Resources Current Lecture Rock Forming of Minerals These are common minerals that make up almost all of the Earth s crust There are only a few dozen members It is only composed of 8 elements on the Periodic Table that make up about 98 of the crust Out of the 4000 minerals discovered the remaining 3900 are rare with less common elements Oxygen in solid form is the primary abundance in the crust Classification of Minerals Common Groups Silicates Silicon Oxygen o Ex Quartz SiO3 Oxides Metal Oxygen o Ex Hematite Fe2O3 Carbohydrates Contains CO3 ions o Ex Calcite CaCo3 Sulfides Metal Sulfur These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Ex Pyrite FeS2 Native Elements Pure elements o Ex Sulfur Gold Silicates Most important mineral group o Comprise most of the rock forming minerals o Very abundant because of the large amounts of Si and O in crust Silicon Oxygen Tetrahedron molecule basic building block o Four Oxygen ions surrounding smaller Silicon ion Silicate Structures Basic building blocks of Silicate come and connect together to form a lot of structures that include o Isolated Tetrahedra Olivine High temperature Individual tetrahedral linked by iron and magnesium Forms small round crystals without cleavage o Ring Structures o Single Chained Proxene Involve Iron and Magnesium Two distinct cleavages at 90 degrees Augite is most common o Double Chained Amphibole Group Complex Fe Mg silicates Have variety of ions Two perfect cleavages with 124 and 56 degree angles Hornblende is most common mineral o Sheet or Layered Structures Mica Group Complex Silicate Have one direction of perfect cleavage Peel off layers o Complex 3D Structures Feldspar Group Most common mineral group 3D framework that have two directions of perfect cleavage at 90 degrees Orthoclase and Plagioclase are most common Quartz Only common mineral with just Si and O Exhibits conchoidal fracture Resistant to erosion Clay Minerals o Clay is general term used to describe complex minerals o All have layered and sheet structures o Make up large percentage of soils Classification of Non Silicates Important minerals o Oxides Not volumetrically abundant but are locally concentrated to make metal ores o Carbohydrates Calcite and Dolomite are two most important Most caves form in limestone a rock primarily made up of Calcite o Sulfides Can be important ores for metals but can form sulfuric acid o Native Elements Made up of only one element Most are rare o Sulfates o Halides o Phosphates Mineral Resources Is a loose term for the natural solid material we use for profit Ore Deposits mineral deposits that are high enough to concentration that become economically viable o Depends on economy Depends if the money for the mineral is worth the money to spend getting it
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