1. Minerals

2. A mineral:  Is a naturally occurring inorganic solid  Has a specific chemical makeup  A mineral has a specific crystalline structure

3.  Minerals are formed by natural processes  Minerals are inorganic (not alive EVER!!!)

4.  The atoms in a mineral are arranged in particular patterns  A crystal is a solid in that has it’s atoms in a specific repeating pattern

5.  Remember that solids have definite shapes and volumes  They are primarily rigid  They also have specific unique chemical compositions

6.  There are about 3000 minerals in Earth’s crust  But only about 30 are common  About 8 to 10 are called rock forming minerals because they make up most of the rocks in Earths crust

7.  The most common elements are: ◦ Oxygen46.6% ◦ Silicon27.1% ◦ Aluminum8.1% ◦ Iron5% ◦ Calcium3.6% ◦ Sulfur2.8% ◦ Potassium2.6% ◦ Magnesium2.1%

8.  Magma is less dense than the surrounding solid rock so it can rise upward to cool.  How it cools decides what type of rock is formed  Slowly cooled magma becomes rock with large crystals  Quickly cooled magma has small crystals

9.  When a liquid gets full of a dissolved substance, it is supersaturated  This allows minerals to form  Individual atoms bond and mineral crystals precipitate (form into solids in the solution)

10.  Minerals are identified by their chemical and physical properties ◦ Crystal form ◦ Luster ◦ Hardness ◦ Cleavage ◦ Fracture ◦ Streak ◦ Color ◦ Texture ◦ Density ◦ Specific gravity ◦ Special properties

11.  Crystal form ◦ Some minerals form distinct crystal shapes that are immediately recognized ◦ Halite (table salt) forms perfect cubes ◦ Quartz crystals have double pointed ends and six sided crystals  Luster ◦ Is the way a mineral reflects light ◦ Two types of luster  Metallic luster and nonmetallilc luster

12.  Hardness ◦ Is a measure of how easily a mineral can be scratched ◦ Friedrich Mohs developed a scale to compare the hardness of minerals ◦ Talc is the softest and Diamonds are the hardest.  Cleavage and fracture ◦ The atomic arrangement of a mineral determines how it will break ◦ They break along their weakest planes ◦ A mineral that splits easily and evenly along one or more planes is said to have cleavage

13.  Streak ◦ A mineral rubbed across an unglazed porcelain plate can leave a colored powdered streak on the plate ◦ Streak is the color of a mineral when it is broken up and powered ◦ Non-metallic minerals usually leave just a white streak ◦ Metallic minerals leave colors although the color may not match the solid mineral color  Color ◦ Is caused by the presence of trace elements or compounds within a mineral

14.  Define a mineral  Describe how minerals form  Classify minerals according to their physical and chemical properties