Minerals

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

A. Naturally occurring A mineral has to be found on the earth's surface or dug up out of the crust, not made in a lab somewhere by people. Examples of man- made objects are bricks, cement, and glass

B. Inorganic This means that they do not come from living things. Since coal forms naturally in the crust and from living things it is not a mineral  

C. Solid Solids are substances that have a definite shape and a definite volume. The particles are tightly packed and can not flow freely.

D. Crystal structure The atoms that minerals are made of are connected to each other in a pattern.  This pattern is called its crystal structure. The flat sides form faces

E. Definite Chemical Composition This means that there is a specific chemical formula for each mineral.  The mineral pyrite is made of 1 atom of iron for every 2 atoms of sulfur. (FeS2) Pyrite will have the same chemical formula regardless of where it is found.

Identifying Minerals Each mineral has its own characteristics or properties that help you identify it.

Identifying Minerals a. Hardness Hardness is one of the best clues to identify a mineral. Mohs hardness scale ranks ten minerals from softest to hardest. A mineral will scratch any mineral softer than itself.

Identifying Minerals B. Color Color is a physical property that is easily observed, however not many minerals have distinct colors. Malachite is always green Azurite is always blue malachite

Identifying Minerals C. STREAK Streak refers to the color of a mineral’s powder. Testing a mineral’s streak is done on an unglazed piece of tile. Although a mineral’s color may change its streak color does not.

Identifying Minerals D. Luster Luster is another simple test for determining a mineral. Luster refers to how a mineral reflects light. Metals are often shiny other minerals may be glassy,waxy or pearly. Tourmanline has a vitreous (glassy) luster.

Identifying Minerals E. Density The density of a mineral always remains the same. Density measures the “heaviness” of an object.

Identifying Minerals G. how it breaks The way a mineral breaks apart also can help identify it. If it splits easily along flat surfaces it has a property called cleavage. However if it does not break evenly it has a characteristic type of fracture. Calcite has cleavage Copper will fracture

Minerals are the source of metals, gemstones, and other materials used to make many products.

Gemstones Gemstones are hard, colorful and have a brilliant or glassy luster. Gemstones are valued for their color, luster and durability. Once cut a gemstone is referred to as a gem.

Metals Metals are useful because they can be stretched into wire or hammered into sheets. Metal is use in making tool framing buildings and even the filament in a light bulb.

Other uses Some minerals are used in foods, medicines, fertilizers and other building materials.