Chapter 1: Minerals of the Earth’s Crust

What is a Mineral? A Mineral has 4 Characteristics: Solid Crystalline Structure Non-Living Formed by Nature (not man made)

What is a Mineral Made out of? Atoms - smallest particle that can exist of a substance Elements - a pure substance that cannot easily be broken down Compounds - different elements combine to form larger substances Crystals - solid, geometric forms of minerals created by a repeating pattern of atoms Minerals

Most minerals can be classified based upon their chemical composition (the chemicals that make them up) Ex: Sodium (Na+) and Chlorine (Cl-) form a compound called Sodium Chloride (NaCl) which is a mineral called Halite or table salt.

Minerals can be divided into 2 major groups: 1.silicate minerals 2.nonsilicate minerals

Made of silicon and oxygen 90% of Earth’s crust Examples: – Feldspars – Biotite Mica – Quartz

Feldspars - Most abundant surface rock, made up about 50 to 60% of Earth’s crust Biotite Mica – Shiny & soft, separate into sheets when they break Quartz – Basic building block of many rocks, crystal looking **Can one rock contain all of these minerals? YES or NO

Do not contain silicon and oxygen Examples include: Native elements- (Copper, gold, silver, platinum, diamond) Carbonates- (cement & fireworks) Halides- (detergents) Oxides- (aircraft parts & paint) Sulfates – (cosmetics, toothpaste, paint) Sulfides- (batteries, medicine, electronics)

Identifying Minerals - Minerals can be identified by…..their characteristics. Color Luster Streak Cleavage Fracture Hardness – Mohs’ Scale 1-10, talc-diamond Density Special Characteristics

Minerals come in a variety of colors. Some colors are due to factors such as impurities and weather conditions. Color

Amethyst

Luster This is the way a mineral reflects the light. A mineral’s luster can be: Metallic (shiny) Submetallic (a little shiny) Nonmetallic (dull) Vitreous (glassy) Pearly (opalescent)

Metallic mineral

Semi-Metallic Mineral

Non-Metallic Minerals

Streak This is the color a mineral appears when it is rubbed against an unglazed piece of porcelain Streak Test

Cleavage: this is the way that a mineral breaks. Some minerals break into flat sheets, such as Mica, while others break in angles, such as diamonds

Fracture The tendency of some minerals to break unevenly along curved or irregular surfaces

This is a mineral’s resistance to being scratched. Some minerals can be scratched easily, such as talc, while others are nearly impossible to scratch, such as diamonds. Hardness

Density This is how much matter is in a given space. Mineral’s densities vary, for example: gold’s density is much greater than that of mica

Some minerals have special properties. Identified by other characteristics such as….. 1.Fluorescence – glow under UV light 2.Chemical reaction – Fizzing when combined w/acid 3.Optical Properties – Calcite will cause double images 4.Radioactivity – Contain radium or uranium 5.Magnetism- attract iron 6.Taste – Salty, bitter, sour

Fluorescence

Mining Large enough deposit of an element to gain a profit is called an ore.

2 Types of Mining 1.) Surface Mining Removal of minerals or other materials at or near the Earth’s surface. Types of surface mines include: – Open pits – Strip mines – Quarries Materials mined in this way include copper ores and bauxite. 2.) Deep Mining (Subsurface) Drilling deep passageways below Earth’s surface to reach the ore. Diamonds and coal are mined this way. – Can be VERY DANGEROUS!!!!

Products Made from Mining MINERAL  METAL  USES Mineral in Ground Metal turned into Product made Chalcopyritecoppercoins, electrical wire Galenaleadbatteries, paint Berylberylliumbicycle frames, airplanes Chromitechromiumstainless steel, cast iron

Responsible Mining Mining can disturb habitats of plants and animals Waste products from the removal of the ore can also cause pollution

Reclamation Reclamation – law since 1970 states that after mining you must return land to its original state after the mining is completed. Very expensive and time consuming! Mining gives us the minerals we need, but it also creates problems. – Can destroy or disturb the habitats of plants & animals. – The waste products from a mine can get into water sources, polluting both surface water and ground water.

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