COLOR  The color of the mineral you observe with your eyes.  The streak color does not always match the minerals color due to impurities, water, and air.  Color depends on the internal arrangement of atoms.  NOT the best way to identify a mineral.

STREAK  The color of the powder of a mineral.  The streak is not always the same color as the color of the mineral.  The streak is not affected by water and air, so it’s more reliable to identify minerals than color.

LUSTER  The way in which a mineral reflects light.  Luster can be metallic or nonmetallic.  Some common words to describe nonmetallic luster are glassy, waxy, silky, and earthy.

HARDNESS  A measure of the ability of a mineral to resist scratching.  Mohs’ Hardness Scale.  Talc is the softest, and diamonds are the hardest.  Measured on a scale of 1-10

DENSITY  The ratio of the mass of a substance to the volume of a substance.

CLEAVAGE  The splitting of a mineral along smooth flat surfaces.  Clean breaks.

FRACTURE  The manner in which a mineral breaks along either curved or irregular surfaces.  Breaks in rough, jagged pieces instead of clean lines.