Minerals

What is a mineral? 5 Characteristics of a mineral Naturally Occurring Naturally Occurring Inorganic (Not Living) Inorganic (Not Living) Always a solid Always a solid Has a definite chemical composition Has a definite chemical composition Atoms are arranged in a repeating pattern (creates crystals) Atoms are arranged in a repeating pattern (creates crystals)

Mineral Identification Scientists identify mineral based on their properties. Scientists identify mineral based on their properties. Color and appearance are 2 clues that we use to identify minerals. Color and appearance are 2 clues that we use to identify minerals. Are color and appearance enough? Are color and appearance enough? No WAY! No WAY!

Hardness The measure of how easily a mineral can be scratched by other minerals. The measure of how easily a mineral can be scratched by other minerals. To compare hardness a list of common minerals and their hardness was developed by Friedrich Mohs. To compare hardness a list of common minerals and their hardness was developed by Friedrich Mohs. We call is the Mohs scale. 1 = Softest, 10 = Hardest. We call is the Mohs scale. 1 = Softest, 10 = Hardest.

Luster Luster describes how light is reflected from a minerals surface. Luster describes how light is reflected from a minerals surface. Luster is either metallic (shiny and metal – like) or non-metallic (not shiny) Luster is either metallic (shiny and metal – like) or non-metallic (not shiny)

Color The color of a mineral can serve as a clue to it’s identity. The color of a mineral can serve as a clue to it’s identity. However, color is NOT enough to determine the identity of a mineral. However, color is NOT enough to determine the identity of a mineral. Ex: Quartz Ex: Quartz

Streak Streak is the color of a mineral when it is broken down into a powdered form. Streak is the color of a mineral when it is broken down into a powdered form. When a mineral is rubbed across a Streak Plate, the mineral that is left behind is powdered. When a mineral is rubbed across a Streak Plate, the mineral that is left behind is powdered. The streak test will only work for minerals that are softer than the streak plate. The streak test will only work for minerals that are softer than the streak plate. Why? Why?

Cleavage and Fracture Cleavage is a property that minerals have when they break along smooth, flat surfaces. Cleavage is a property that minerals have when they break along smooth, flat surfaces. Fracture is a property that minerals have when they break along rough, jagged surfaces. Fracture is a property that minerals have when they break along rough, jagged surfaces.

Other Properties Some minerals are magnetic (Ex: Magnetite) Some minerals are magnetic (Ex: Magnetite) Some minerals fizz when they come in contact with an acid. (Ex: Calcite) Some minerals fizz when they come in contact with an acid. (Ex: Calcite)

Video Clip Questions 1. How many minerals found in nature? 2. About how many are important in developing rocks? 3. How many properties tests are used to identify minerals? 4. Which is more dense? Nonmetal base or metal base?