What is a mineral?
Properties of Minerals Mineral 5 characteristics: naturally occurring (not made by people) inorganic (cannot come from living things) solid (definite shape and volume) crystal structure (regular, repeating pattern)
Element pure substance that cannot be broken down makes up all minerals made of one kind of atom (smallest part of an element) Compound two or more elements chemically combined Crystal Shape determined by arrangement of atoms
Silicate Minerals Nonsilicate Minerals contains a combo of silicon, oxygen, and one or more metals make up more than 90% of crust ex. quartz, feldspar, mica does not contain compounds of silicon and oxygen ex. copper, calcite, fluorite
Identifying Minerals Color Streak -easily observed physical property -only a few minerals ALWAYS have the same color -color of a mineral s powder -streak color does not vary, even though physical color can -observe by rubbing on porcelain tile
Luster -how light reflects off surface -ex. shiny, metallic, glassy, earthy, waxy, pearly Density -mass in a given space (M/V) -density always stays same, no matter what size the mineral is
Hardness Mohs Hardness Scale -test invented by Friedrich Mohs -ranks 10 minerals from softest (1) to hardest (10) -scratch test -softest = talc -hardest = diamond
Cleavage splits easily along flat surfaces -depends on how crystals are arranged -ex. mica Fracture -breaks apart in an irregular way -shell shaped, jagged, crumble -ex. quartz
Special Properties -fluorescence: glows under UV light -magnetism -optical: bends light -reactivity: reacts to acids
How Minerals Form Crystallization Geode -atoms are arranged to form materials with a crystal structure -forms two ways: 1. magma/lava 2. materials dissolved in water -round, hollow rock -lined with mineral crystals
Minerals from Magma/Lava -form as hot magma cools inside crust; lava hardens on surface -liquid to solid state -size of crystals depends on rate at which magma cools *deep below surface cools slowly = large crystals *close to surface cools quickly = small crystals
Solution -mixture -one substance completely dissolves in another Minerals from Solution -elements and compounds dissolved in water leave a solution -crystallization occurs
Formed from Evaporation -when solutions evaporate, water turns to gas and leaves minerals behind to crystallize -ex. seas evaporate leaving behind gypsum and calcite Formed from hot water solutions -magma heats ground water -minerals dissolve in water -as solution cools, minerals leave solution and crystallize -ex. Gold, copper, sulfur, pyrite.
Vein -narrow channel of mineral different from surrounding rock -solutions of hot water and metals flow thru cracks in rock -metals crystallize into veins -resembles streaks of fudge in ice cream
Mineral Resources Gemstones -hard, colorful mineral with glassy luster -valued for color, luster, and durability -mainly for jewelry and decoration
Metals -source of metals like aluminum, iron, copper, and silver -useful for: *stretching into wires, *flattening, *hammering without breaking
Other Uses Ore -used in foods, medicines, fertilizers -ex. talc = talcum powder quartz = glass & watches gypsum = cement, stucco -rock that contains metal or useful mineral -metals & minerals can be separated from ore
Prospector -anyone who searches for ore deposit -look for certain features on earth and study maps of rocks Mining -three types: strip mines open pit mines shaft mines
Strip Mines -earthmoving equipment scrapes away soil to expose ore
Open Pit Mines -earthmoving equipment digs a big pit and removes ore deposits
Shaft Mines -network of tunnels that follow veins of ore
Smelting -process in which metal is removed from rock (ore) -ore is mixed with other substances and melted