Based on Discover God’s Creation Minerals and Rocks Based on Discover God’s Creation Chapter 8-1, 2 & 3 By Rebecca K. Fraker

Matter Matter is anything is anything—solid, liquid, or gas—that has mass and takes up space. Matter on earth is made up of one or more of the 92 naturally occurring atoms or elements, substances that normally do not change into other substances.

Elements Each element has special properties that identify it. While elements do not change, they can combine with others to form compounds. When hydrogen and oxygen combine they form a common compound –water.

Other examples of compounds:

Minerals Minerals are elements or compounds that occur in Earth. Gold, silver, and copper are single-element minerals.

Minerals Most minerals, however, are compounds made up of two or more elements. Table salt is made of sodium and chlorine. plus salt Sodium Chlorine

All minerals share four features: They occur naturally in the environment. The do not come from living things. Each has unique properties and composition. Their atoms are arranged in an orderly pattern.

How are minerals found? Minerals are often found in concentrated deposits. Some minerals, such as quartz and feldspar, form as magma cools in the cavities or cracks in the crust. Heavy minerals, such as gold, are deposited as water washes them into rivers and they settle to the bottom.

Other Minerals Still other minerals, such as gypsum and halite (rock salt) form as the water they are dissolved in evaporates from shallow lakes.

Identifying Minerals How do you tell the difference between fool’s gold and real gold? Geologists use several tests to identify the properties of minerals.

Hardness Test The Mohs’ scale indicates the hardness of a mineral. It is based on 10 minerals. Number 1 is the softest, and Number 10 is the hardest. A mineral is tested by seeing which other minerals it will scratch. If it scratches 1,2,and 3, it has a hardness of 4. Diamond has a hardness of 10 and can scratch all other minerals.

Mohs’ Scale An easy way to test hardness is to use your fingernail, a penny, a knife blade, and glass. Fingernail=1 Copper penny=3 Knife blade=6 Glass=8

Streak Test Some minerals are identified by their color. Sulfur, for example, is bright yellow. When the color of a mineral is hidden by dirt, you can do a streak test by rubbing the mineral across a rough piece of tile or a metal file. The color of the streak helps identify it. Fool’s gold leaves a dark-green streak. Real gold leaves a golden streak.

Luster Test Luster refers to how a mineral reflects light. A mineral can have a metallic or nonmetallic luster. Galena, which shines like a piece of metal, has a metallic luster. Quartz has a nonmetallic luster because ti is glassy, waxy, or dull in appearance.

Crystal-Shape test The crystals of each mineral have a specific shape. Salt crystals are always shaped like a cube. If you can see the shape of a crystal, you can identify the mineral. But that is not always easy.

Crystals Salt amythest sulfur feldspar

Cleavage/Fracture Test If a mineral is hit hard enough, it will break or fracture. Some minerals, like fool’s gold, break unevenly. Others, such as mica, split into thin sheets. This quality is called cleavage.

Other tests A few minerals contain iron and are attracted by a magnet. Some minerals contain carbonates that bubble and fizz when acid touches them. Rock salt (halite) can be identified by its taste, while sulfur when scratched gives off a rotten eggs smell.

Other tests Calcite splits light into two beams that form a double image. Some minerals are fluorescent. They normally look dull, but are bright and colorful under ultraviolet light.

Metals Minerals such as gold, copper, and aluminum are metals They have luster and can be hammered into flat sheets or drawn into a wire. Metals are good conductors of heat and electricity. Because of these qualities, they are widely used.

Mineral or Rock? Minerals are single elements or combinations of elements. Rocks are mixtures of various minerals. In mixtures, ingredients do not chemically combine and change; they simply stick together.

Rocks Concrete and granite provide examples that demonstrate such mixtures. Rocks are often identified by the minerals that stick together to form them. Concrete is sand, cement, and water mixed together. It then is poured into a shape and hardens.

Granite Granite is a common rock used for buildings, monuments, and counter tops. Feldspar is the light-colored part of granite, quartz makes up the clear crystals, and biotite and mica are the dark-colored specks.