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

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 Mineralsa. 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 MineralsB. Color • Color is a physical

property that is easily observed, however not many minerals have distinct colors.

• Malachite is always green

• Azurite is always bluemalachite

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 MineralsD. 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 MineralsG. 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.