Mineral Notes. The crust is made of mixtures of naturally occurring compounds and elements called minerals.

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1 Mineral Notes Mineral Notes Earth s crust is the solid outermost layer of Earth. It is thicker under the continents and thinner under the oceans. The crust is made of mixtures of naturally occurring compounds and elements called minerals. Out of all the elements in the periodic table, 90 are found naturally on Earth. Out of those elements this table shows some of the most common rock forming elements.

2 Look at Reference Table Most minerals are made from Silicon and oxygen Examples: Quartz: SiO 2 Feldspar: KAlSi 3 O 8 Garnet: Fe 3 Al 2 Si 3 O 12

3 Minerals form in 3 main ways 1) As ground water flows over or through rock it dissolves some of the minerals creating charged molecules or atoms called ions. Eventually the water gets to a place where it stops moving and may evaporate. As the water changes to a gas it leaves the dissolved ions behind which combine to make a compound. This mineral material crystallizes to form a solid. If you have "hard water" it is from dissolved minerals. 2) Charged ions in molten rock called magma or lava combine as the molten rock cools. 3) When rock is heated up or pressurized during mountain formation, the heat / pressure forces ions to re organize making new minerals What is a mineral? 1)Naturally occurring not man made 2) Non organic not made by a living organism 3) Specific chemical composition only one chemical formula i.e. Quartz SiO 2 or Halite NaCl 4) Distinctive physical propertiesunique/unchanging 5) Crystalline (crystal like) structure Minerals have an organized atomic arrangement that creates its properties Single chain Double Chain Framework

4 Ways to classify a mineral Color is perhaps the most obvious identification technique. But color can be misleading Minerals can have multiple color variations The mineral calcite can be clear, white, yellow and pink Also, different types of minerals can have the same color Olivine and garnet can both be green and many, many minerals can be white or clear. 1) Its shape and how it breaks This quality refers to how a mineral splits or breaks when hit with a rock hammer. Minerals break along planes of weakness called Cleavage plains Some minerals like Mica will peel off in layers Others will break with specific 3 Dimensional pattern Cleavage: parallel planes of weakness along which minerals can break. Cleavage results in flat even sides. Steps are also a common indicator. Fracture: mineral breaks with uneven, jagged surfaces. The sample usually shows no specific geometric shape. Fracture: mineral breaks with uneven, jagged surfaces. Looks like broken glass. 2) Streak: A mineral s Streak is the powder that a mineral leaves behind when scratched against an unglazed porcelain tile A mineral s streak is not necessarily the same color of the mineral Hematite is grey with a redish brown streak This parameter can help determine the type of mineral if two minerals have the same color. A certain mineral's streak is always the same color, even though the sample colors can vary.

5 3) Hardness is a Property that indicates how easily a mineral can be scratched Hardness is determined by the Mohs' Hardness Scale which goes from 1 10 Talc has a hardness of 1 A fingernail has a hardness of 2.5 You can scratch talc with your fingernail Glass has a hardness of 5.5 You can scratch a fingernail with a piece of glass Diamond has a hardness of 10 nothing scratches diamond Hard mineral scratches glass Soft your fingernail scratches the mineral Medium fingernail cannot scratch the mineral and the mineral cannot scratch glass. Uses Saw Blades Ruby, Saphire Emerald Watches, Abrasives Floor Tiles Fertilizer Tooth Paste Cement Sheet Rock Baby Powder 4) Luster is the amount of light reflected by a mineral Adamantine diamond like Glassy/Vitreous Pearly Resinous Waxy Dull *Metallic shines like unpainted metal. i.e penny, nail *Non metallic looks dull, shiny, plastic like, earthy Metallic Vitreous non metallic Both are shiny but only the GOLD one or Pyrite is metallic

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