Earth’s Materials

1. Earth’s Materials

2. Minerals • On the periodic table, of the first 92 elements: 90 are found in the Earth • The crust is the outermost layer of Earth, and includes all continental material and materials that form the ocean bottom. • Extends 10km beneath the continents

3. Major Elements in the Earth’s crust

4. What’s a mineral? • A mineral is a naturally occurring element of compound that is inorganic, solid, and has a crystalline structure • Inorganic means that minerals are materials that are not produced by living organisms • The composition of minerals are indicated by their chemical formula • Example: Fluorite= CaF2

5. Physical Properties • A mineral has a particular chemical composition, although can sometimes vary due to small impurities • Example: Ruby vs. Sapphire

6. Example • Ruby vs. Sapphire • Both contain corundum, but Ruby has more chromium then Sapphire

7. Atom Arrangement • Some properties are controlled by orderly arrangement of atoms in a mineral’s structure • This pattern is what makes a mineral crystalline • The arrangement of atoms and the bonds between them can reflect the way a mineral breaks, how hard it is, and what type of crystal shape

8. How minerals break • Cleavage: the ability of a mineral break along plans that cut across relatively weak chemical bonds, a smooth, flat surface. • Fracture: an irregular break

9. Hardness • Bonds connecting atoms in materials often have different strengths • When your scratch a mineral with another mineral the scratch forms as bonds in the material are broken.

10. Mohs Scale of Hardness

11. Luster and Streak • The way a mineral reflects light is known as luster • Metallic • Nonmetallic • The color of a mineral in powdered form is called streak • The streak may be the same color as the mineral