Minerals of Earth’s Crust

What is a Mineral? 1. Inorganic, or not made from living matter. Occurs naturally or not man made. Atoms arranged in regular repeating form. Made up of a consistent chemical composition.

Inorganic? 1. Is the mineral made from living material? Then it is organic. 2. Anything that was once living is called organic. Therefore, coal, which was once living is not considered a mineral.

Naturally Occurring? Does it occur in naturally in nature? Is it man made? If so it is not a mineral.

Crystalline Solid? Does it have a regular repeating crystalline structure? The crystalline structure is made up of oxygen and silicone. These two minerals which make up over 70 percent of the mass of the Earth.

Earth’s Composition 28% 47%

Oxygen and Silicone as Silicate Minerals make up almost 75% of the Earth.

Kinds of Minerals 1. Silicate minerals that have Silicone, Si and oxygen, O 2. Nonsilicate minerals that do not have O and Si

Structure of Silicate Minerals

Silicone-oxygen Tetrahedron

Silicate Minerals Arrangements

Properties of Minerals A scientist that studies minerals is called a mineralogists. There are seven properties of minerals:

1. Color 2. Streak: more reliable. Color of the mineral in powdered form. 3. Luster: reflects light

4. Cleavage and Fracture: Cleavage = smooth surfaces Fracture = uneven surface 5. Hardness: Mohs hardness scale 6. Crystal Shape 7. Density = mass divided by volume

Mohs Hardness Scale A 1 on the scale means the mineral is very soft, like talc. A 10 on the scale means the mineral is very hard, like diamond.

Orthoclase (Feldspar) HARDEST Diamond 10 Corundum 9 Topaz 8 Quartz 7 Orthoclase (Feldspar) 6 Apatite 5 Fluorite 4 Calcite 3 Gypsum 2 Talc 1 6.5 Steel file 5.5 glass 3.5 copper penny 2.5 fingernail SOFTEST

The End