Chapter 1: Minerals of the Earth’s Crust

A mineral is a naturally occurring, inorganic solid that has a definite chemical composition and a crystal structure.

A mineral’s atoms are arranged in a regular, repeating pattern. This is called a crystal pattern. Every mineral has its own characteristic crystal structure, which makes them easy to identify.

Minerals have certain physical properties that can be used to identify them. 1. color: some minerals have a characteristic color, which makes them easy to identify. Many minerals can appear as different colors, so this isn’t the best property to use. 2. luster: this is the unique way that a mineral reflects light. Luster can be either metallic (shiny) or nonmetallic (dull)

3. hardness: the ability to resist being scratched. Hardness is measured using the Mohs Scale (1-10).

4. streak: the color of the powder of a mineral when scratched on a hard surface. This can be very different than the color of the mineral!

5. cleavage, fracture: these terms describe how a mineral breaks. Cleavage is when a rock breaks along a flat, smooth surface. Fracture is when the rocks break along a jagged, rough surface.

Minerals have been an important resource for thousands of years! Today, minerals serve as raw materials for many common everyday products. Ore: a naturally occurring, combination of both metals and nonmetals.

Metals: shiny surfaces, good conductors of heat and electricity, malleable, ductile Nonmetals: dull surfaces, poor conductors of heat and electricity, brittle

Gemstones: a mineral that can be cut and polished for jewelry. These are very rare, and are usually very expensive! Ex- diamond Blue Diamond: 7.8 million US dollars!