What is a Mineral? Pages 45-47
Mineral –
a naturally occurring, inorganic solid with a definite chemical composition (same matter throughout) and an orderly
arrangement of atoms or ions
Naturally Occurring
-only 30 common minerals (10 minerals are rock forming)
Definite Chemical Composition
--same chemical formula (make-up) throughout
-some made of only one element throughout & some made of a combination of elements
Crystalline Form
-minerals form predictable crystal patterns due to repeating atom arrangement
-internal arrangement of atoms determines crystal shape (ex. salt crystals are cubes)
Solid
-all minerals are solid (tightly packed atoms w/definite shape and volume), but not all solids are minerals
Inorganic
-not from biologic (living) origins
The Structure of Minerals pages 47-49
Crystal Shape
-occur in many different shapes
-often too small to identify shape
-can use high powered microscopes to reveal orderly arrangement of atoms
Common Minerals
-common rock forming minerals are made of combinations of elements that are abundant in Earth’s crust
-2 most abundant elements in crust are oxygen and silicon
-2 main families of rock-forming minerals are silicates and non-silicates
-silicate is a member of the mineral group that has silicon and oxygen in its crystal structure (ex. olivine & mica)
-non-silicates do not contain silicon (ex. calcite & halite)
How do Minerals Form? 49-51
-form through process called crystallization (particles dissolved in a liquid or a melt solidify and form crystals)
-can form from hot or cold solutions
Minerals from Cool Solutions
-water dissolves minerals from rocks in soil and picks up elements that become dissolved solids
-as water evaporates the solids crystallize out of the water and form minerals (ex. salt from salt water)
-some organisms remove minerals (salts) from water to make shells/reefs
Minerals from Hot Solutions
-water flows through crust into hot environments carrying dissolved solids & some of the dissolved solids form mineral
deposits inside the Earth (ex. gold)
Minerals from Magma
-magma is molten rock stored under Earth’s surface.
-lava and ash are magma that has erupted onto Earth’s surface
-as lava and magma cool, atoms arrange themselves to make mineral crystals
-small crystals form when lava cools quickly on or near surface
-large crystals form as magma cools slowly below surface
Changes in Minerals
-minerals from deep in the crust & mantle are only stable under high temp and pressure
-when brought to surface, changes in temp and pressure, along with erosion cause minerals to break down and form
new minerals
Mineral Resources pages 63-66
-average person uses 22,000kg of mineral resources yearly
-ore – is a mined rock that contains enough concentrations of a desired substance, such as a metal, so that it can be
mined for a profit
Metallic Mineral Resources
-ores of iron and aluminum are some of the most abundant metallic mineral resources
-iron is main ingredient in steel
-metals are used in food industry, such as metal cans
-aluminum is abundant in crust
Rare Metals
-gold occurs in ratio of 1 part gold to 4 billion parts rock (still concentrations large enough to mine for a profit)
-gold is a good conductor and doesn’t corrode
-platinum used in cars to regulate harmful gas emissions
Nonmetallic Mineral Resources
-used for road construction, ceramics, building stone and fertilizers
Gemstones
-gemstone is a rare and attractive mineral that can be worn as jewelry
-ex diamonds & rubies
-Hardness of some gemstones make them useful in abrasives and as cutting tools