Let’s Talk Minerals

WARM UP!! How are rocks and minerals related?

What is a mineral?

It is a naturally occurring, inorganic substance which has a definite chemical composition. It must exist as a solid on Earth under normal conditions! The atoms that make up the substance must be arranged in an orderly structure, so it has a definite crystal structure. What is the opposite of this? Organic, man-made, random composition, and unorganized crystal structure

What causes minerals to have different physical properties? the internal arrangement of their atoms Minerals maybe made up of the same elements and have the same chemical formulas, but due to differences in the environments in which they formed, exhibit different physical properties!

Can you give an example of two minerals which have the same chemical composition but different physical properties? Graphite and diamonds are both made of carbon, and are sometimes found together. Diamonds are formed under extreme heat and pressure, graphite forms when the heat and pressure are not as intense.

Any questions so far?

The Main Physical Properties Used to Identify Minerals Color a poor indicator minerals can be multiple colors many minerals are the same color

The Main Physical Properties Used to Identify Minerals Streak The streak of a mineral is the color it displays in finely powdered form. The streak maybe completely different from the color of the hand specimen. One of the simplest ways of determining the streak of a mineral is to rub a specimen across a piece of unglazed porcelain known as a streak plate.

The Main Physical Properties Used to Identify Minerals Streak the powder form of a mineral more reliable than color

The Main Physical Properties Used to Identify Minerals Luster how light reflects off a mineral metallic non-metallic looks like a metal looks earthy, waxy, greasy or brilliant

The Main Physical Properties Used to Identify Minerals Luster how light reflects off a mineral metallicnon-metallic

Cleavage The Main Physical Properties Used to Identify Minerals the mineral breaks in a predictable pattern because of its arrangement of atoms

Fracture The Main Physical Properties Used to Identify Minerals the mineral breaks randomly

Hardness The Main Physical Properties Used to Identify Minerals Is resistance to being scratched It is NOT the same as breaking! For example: You can break glass easily with steel. However, steel will not scratch glass.

Hardness The Main Physical Properties Used to Identify Minerals MOH’S SCALE OF HARDNESS HardnessMineralHardnessMineral 1 (softest) (hardest) TALC GYPSUM CALCITE FLUORITE APATITE ORTHOCLASE QUARTZ TOPAZ CORUNDUM DIAMOND

Minerals have a definite chemical composition. There are two elements that, by mass, make up most of the Earth’s crust

Minerals have a definite chemical composition. These two elements combine to form compounds called silicates (SiO 4 )

Minerals have a definite chemical composition. They combine in a specific structure called a: silicon-oxygen tetrahedra All silicates have some form of SiO 4 their chemical formula.

Ticket Out The Door Answer the Following Questions: 1.What are the five things required for something to be a mineral? 2.List 5 things that contain minerals. 3.Is liquid mercury a mineral? Why or why not? 4.What two substances have the same chemical make up but look completely different?

Tomorrow we will: Discuss mineral identification Discuss the use of minerals and rocks around us Look at rock and mineral samples