Minerals of the Earth's Crust Chapter 13 Minerals of the Earth's Crust

Vocabulary: Mineral Luster Ore Element Streak Reclamation Compound Cleavage Crystal Fracture Silicate mineral Hardness Nonsilicate Density

Section 1 What is a Mineral? Mineral- is a naturally formed, inorganic solid that had defiant crystalline structure. How to know if something is a mineral: Has to be nonliving. Has to be solid. Has crystalline structure. Must be nature made.

Minerals are made from elements or groups of elements. Element- a substance that cannot be separated or broken down into a simpler substance by chemical means. (single Lego block) Compound- a substance made up of atoms of two or more different elements joined by chemical bonds. (lots of legos)

Crystals Crystals- a solid whose atoms, ions, or molecules are arranged in a definite pattern.

Two GROUPS of Minerals Silicates- a mineral that contains a combination of silicon, oxygen, and one or more element. Silicates make up 90% of the Earth’s crust.

Two GROUPS of Minerals Non- Silicates- a mineral compound that does NOT contain compounds of silicon and oxygen. Non-silicates can contain oxygen and other elements but do not contain silicon.

Section 2 Identifying Minerals Geologists use several ways to identify minerals. We will learn the 7 most common ways to identify minerals by their characteristics.

1. Color We can identify minerals by color. This is not a real good way because air, water, and impurities can affect color.

2. Luster Luster- is the way a surface reflects light. Shiny minerals usually have a metallic luster. Dull minerals usually have a nonmetallic luster.

3. Streak Streak-The color of the powder of a mineral. The streak can be found by rubbing a mineral on a streak plate.

4. Cleavage and Fracture Cleavage- the splitting of a mineral along smooth, flat surfaces. Fracture- the manner in which a mineral breaks along either curved or irregular surfaces.

5. Hardness Hardness- the measure of the ability of a mineral to resist scratching. Mohs Hardness Scale ranks mineral’s hardness from 1 (soft) to 10 (hard).

6. Density Density- the ratio of the mass of a substance to the volume of a substance. Specific Gravity is the ratio of the mineral’s density to the density of water. Ex. Water has a density of 1 g/cm3. Gold has a density of 19 g/cm3. To get gold’s Specific Gravity SIMPLY DROP THE UNITS! Gold’s Specific Gravity is 19.

7. Special Properties Fluorescence - Glow under a black light. Some minerals can be identified by special properties such as: Fluorescence - Glow under a black light. Chemical Reaction - Some minerals will “Fizz” when you put acid on them.

7. Special Properties Optical Properties - some minerals will act like a magnifying glass. Magnetism - Some minerals are magnetic.

7. Special Properties Taste- Some minerals will taste salty. Radioactivity- Some minerals are RADIOACTIVE!!

Section 3 The Formation, Mining, and Use of Minerals What we will learn in this section: Describe the environments in which minerals will form. Compare the two types of mining. Describe two ways to reduce the effects of mining. Describe different uses for metallic and non-metallic minerals.

Mining Mining is the process of getting ore out of the ground. Ore— a natural material whose concentration of economically valuable mineral is high enough for the material to be mined profitably. Mining can be done inside the earth and on the surface.

Types of Surface Mining 1) Surface Mining—where minerals are dug up close to the surface of the Earth. Types of surface mining include: Open Pit Mining—used to remove large, near-surface deposits of economically important minerals. Ex. gold, copper.

Quarry—open pits used to mine building stone, crushed rock, sand and gravel.

Surface Strip Mining— coal is removed in strips.

Underground Mining 2. Subsurface Mining—minerals deep in the Earth are dug out using horizontal passage ways or a vertical shafts.

Effects of Mining Mining gives us mineral we need, but it creates problems. Reclamation—process of returning land to its original condition after mining is complete. Reclamation has been required by law since the 1970s.

The Uses of Minerals Metallic Minerals- are good conductors of heat and electricity. Used in airplanes, cars, computers, and other electronic devices.

The Uses of Minerals Non-Metallic Minerals- are good insulators of electricity and building products. Used in concrete, drywall, toothpaste, glassmaking, etc.

The Uses of Minerals Gemstones are highly valued for their beauty and rarity rather than their usefulness. Used in rings, necklaces, bracelets, and other jewelry.