 All minerals are formed by natural processes, which occur on or inside Earth with no input from humans  Ex: Salt forms from the natural evaporation of seawater (mineral-halite)  Minerals are inorganic  Aren’t made by life processes  Minerals are an element or compound with a definite chemical composition  Ex: Halite-NaCl (gives a distinct taste to food)

 Minerals are crystalline solids  All solids have a definite volume and shape  Not all solids are minerals  crystalline-atoms are arranged in a pattern  Graphite-arranged in layers  Opal-not a mineral because it doesn’t have a pattern

 Is a solid in which the atoms are arranged in orderly, repeating patterns  Crystals with a smooth surface and regular shape developed in a freely open space  Ex: clear quartz (hexagonal shape)  Crystals whose shape can’t be seen on the outside have developed in a tight space  Ex: rose quartz

1. Hexagonal: Ex: Clear Quartz  Surfaces form 120° and 60° angles 2. Orthorhombic- Ex: Barite  Dimensions are unequal-brick like shape 3. Monoclinic: Ex: Orthoclase  Unequal dimensions  1 right angle forms 4. Triclinic: Ex: rhodonite  Exhibits the least symmetry  Unequal in all dimensions

5. Cubic: Ex: Flourite  Crystals are equal in size like a cube  all three dimensions are equal 6. Tetragonal: Ex: Zircon  Like a cubic crystal  One dimension is longer or shorter than the other too

 Natural processes form minerals  2 ways crystals form 1. From Magma:  Magma cools-atoms move closer together  Combine into compounds  Atoms arrange themselves into orderly, repeating patterns  Type and amount of elements determine which mineral will form

 Size of crystals depends on how quickly magma cools  Large crystals form when magma cools slowly  Small crystals form when magma cools quickly 2. From Solution  Crystals form from minerals dissolved in water  Evaporation of H 2 0 causes ions to come together (halite)  If too much of a substance is dissolved in water, ions will come together forming crystals of that substance (don’t need evaporation)

 8 elements form 98% of Earth’s crust  Silicates  most rock-forming minerals belong to this group  Minerals that contain silicon, oxygen and one or more other elements  Silicon and oxygen 2 most abundant elements in Earth’s crust  Carbonates  Contain carbon, and oxygen and other elements  Are rock-forming minerals

 Every mineral has unique physical properties that distinguish them from each other  There are 7 properties scientists look at  Every property you observe in a mineral is a clue to its identity 1. Mineral Appearance:  Color and appearance  Can not just look at these 2 properties because minerals can have the same color and shape

2. Hardness  How easily a mineral can be scratched  Talc is soft and can be scratched with your fingernail  Diamonds are the hardest mineral  Mohs scale  Lists the hardness of ten minerals  Softest talc hardness =1  Hardest diamond=10  Depending on the item you can scratch the mineral with, will tell you its value and what kind of mineral it is

3. Luster  The way a mineral reflects light  Can be metallic-shine like metal  Can be nonmetallic-does not shine like metal  Ex: quartz, calcite, halite, flourite 4. Specific Gravity  Is the ratio of its weight compared with the weight of an equal volume of water  Expressed as a number  Ex: gold’s specific gravity=19  This means that it is 19 times heavier than H 2 O

 Heft is a term used to describe how heavy a mineral sample feels 5. Streak  Is the color of a mineral when it is in a powdered form  Scratched on a piece of unglazed porcelain tile  Streak test only works if the mineral is softer than the tile

6. Cleavage  Minerals that break along a smooth, flat surface  Ex: Mica-breaks apart in smooth layers 7. Fracture  Break with uneven, rough, or jagged surfaces  Ex: Quartz

 Highly prized minerals because they are rare and beautiful  Most are special varieties of a particular mineral  Clearer, brighter or more colorful than original mineral  Table 2

 Some gems are spectacular and play a role in history  Ex: Cullinan Diamond  Was cut into 9 main stones and 96 smaller stones  Part of British crown jewels  Ex: blue Hope diamond  Gained reputation for bringing bad luck

 Some gems are useful  Diamonds used as industrial abrasives and cutting tools  Rubies used to produce specific types of laser light  Quartz crystals used in electronics and as timepieces  Most industrial diamonds and other gems are synthetic-made by humans

 Mineral or rock is an ore if it contains a useful substance that can be mined at a profit  Ex: Hematite-contains iron  Iron used to make pans, ships  Aluminum comes from the ore bauxite  Refining of aluminum  Aluminum oxide powder is separated from bauxite  Powder is converted into molten aluminum by smelting- substance is melted to separate it from unwanted materials that remain  Aluminum used to make bicycles, cans, foil

 Mineral deposits left behind that fill in the open spaces created by weaknesses in rocks  Weaknesses include cracks, faults, and surfaces between layered rocks  Vein minerals fill in empty spaces after rocks collapse  Ex: Sphalerite  Importance source of zinc-used in batteries

 Titanium is a durable, lightweight, metallic element  Comes from minerals that have it  Sources of titanium are ilmenite and rutile  Common in rocks that form when magma cools and soldifies  Titanium used to make cars, eyeglass frames, golf clubs, bicycles, hip replacement