Identifying Minerals  There are seven ways to identify a mineral.  1. Color  2. Luster  3. Streak  4. Cleavage and Fracture  5. Hardness  6. Density  7. Special properties

Color  The same mineral can come in a variety of colors.  For example, in its purest state quartz is clear. But some types and varieties can con contain impurities and can be of a variety of colors.  Other factors can change the appearance of minerals.  The mineral pyrite, often called fool’s gold, normally has golden brown color. But if it is exposed to air and water for a long period of time, it can turn brown or black.  Color is usually not the best way to identify a mineral.

Luster  The way a surface reflects light is called luster.  When we describe an object as dull or shiny, we describe its luster.  Minerals can have a metallic, sub metallic or nonmetallic luster.  If a mineral is shiny, it has a metallic luster.  If a mineral is dull, its luster is either sub metallic or nonmetallic.

Streak  The color of a mineral in powered form is called the mineral’s streak.  A mineral’s streak can be found by rubbing the mineral against a piece of unglazed porcelain called a streak plate.  The mark left on the plate is the streak.  The streak is a thin layer of powered mineral.  Streak is not affected by air or water.  Using streak is more reliable than using color in identifying a mineral.

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

Hardness  A mineral’s resistance to being scratched is called hardness.  To determine the hardness of minerals, scientist use Mohs hardness scale.  The greater a mineral’s resistance to being scratched is, the higher the mineral’s rating.

Density  Is the ratio of mass of a substance to the volume of the substance.  Density= Mass/volume  The ratio of an object’s density to the density of water is called Specific gravity.

Special properties  1. Fluorescence  2. Magnetism  3. Chemical reaction  4. Taste  5. Optical properties  6. Radioactivity

Mohs hardness scale