minerals ppt great explaination

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Ngày đăng: 30/11/2016, 08:06

In 2008, crystals up to 39 feet long were found in a cave in Mexico at a depth of 1000 feet The cave is extremely hot, with air temperatures reaching 136 °F with 90 to 99 % humidity The cave is relatively unexplored due to these conditions Without proper protection, people can only endure about ten minutes of exposure at a time See the suits Mineral Formation The Earth’s crust is made up of two things: • Minerals and Rocks Coal Gneiss Scoria Rocks are Minerals are individual crystals of all the same stuff combinations of minerals ***You should see lots of different minerals in every single rock Main Concept: Minerals are the What is a mineral? building blocks of rocks! There are five main criteria for something to be a mineral: a) It must be solid a) It must occur naturally (not man-made) b) It is made of non-living material (never alive) c) It has a definite chemical formula (NaCl=salt) d) It has a crystal structure (Precious?) Examples: ***Notice how each is one single type of crystal! • Amethyst • Galena Calcite Gold Garnet Pyrite Where minerals come from?  Mineral crystals can form in two main ways: From stuff dissolved in liquids (Evaporation & Hot Water) From Cooling molten material Minerals & Crystals from Magma & Lava “Extrusive” Cooling: Lava cools Fast (Short Time = Small Crystals) •Minerals form from hot magma as it cools inside the crust, or as lava cools on the surface •When these liquids cool to a solid, they form crystals (minerals) •Size of the crystal depends on time it takes to freeze into a solid “Intrusive” Cooling: Magma cools slowly (Long Time = Large Crystals) Minerals Minerals Crystal Crystal Size Size When the hot material cools fast, it has smaller crystal size When it cools slowly, it has large crystals Granite You can see individual crystals in Granite = cooled slowly Rhyolite You can’t see many individual crystals in Rhyolite = cooled very fast Minerals formed by Evaporation  Some minerals form when solutions/mixtures evaporate:  When water evaporates, it leaves behind the stuff that’s dissolved in it  The longer it takes to evaporate, the larger the crystal  i.e salt & water – ocean,  Halite, Gypsum, Calcite ***All the white stuff = salt mineral crystals that formed when the water of this lake evaporated The mineral material was left behind These salt crystals formed from salt water because as the water evaporated, the salt wasn’t dissolved anymore So the chemical energy in salt takes over and crystals form Do you notice the characteristic cubic crystalline shapes? How we identify Minerals? We use the different physical and chemical properties of the mineral to identify it from other different minerals Luster: Describes how light is reflected from a minerals surface Streak: Is the color of the minerals powder when dragged across a surface Crystal shape: Different minerals make different crystal shapes Hardness: Hardness is determined by a “scratch test” Color: Every mineral has some natural color…ex: Gold, Blue, Clear… Etc: There are many other types of properties we use but these are the big ones Special Properties • Some minerals display strange properties • These can include: Magnetism, fluorescence, and reactivity Fizzing! The particles of minerals of this rock act like magnets These minerals glow The minerals in in the dark this rock react A black light really brings it out! with acid [...]...Special Properties • Some minerals display strange properties • These can include: Magnetism, fluorescence, and reactivity Fizzing! The particles of minerals of this rock act like magnets These minerals glow The minerals in in the dark this rock react A black light really brings it out! with acid
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