HARDNESS • Mohs hardness scale – ranks ten minerals from softest to hardest. 1 is softest, 10 is hardest. Use the scratch test.
COLOR • Easily observed physical property • Can only be used to identify minerals that always have their own characteristic color.
STREAK • Streak is the color of its powder. • Streak color never varies even if colors do.
LUSTER • Luster describes how a mineral reflects light from its surface. • Terms to describe luster – shiny, glassy, pearly, greasy, earthy.
DENSITY • Mass in a given space, or mass per unit volume. • To calculate, divide mass by volume. • Density = mass / volume
CRYSTAL SYSTEMS • 6 groups of crystals based on number and angle of the crystal faces
CLEAVAGE and FRACTURE • Cleavage: splits easily along flat surfaces • Fracture: breaks apart in an irregular way.
Special Properties • There are many special properties that can be used to identify minerals. • Flurescence, chemical reaction, optical properties, radioactivity, taste (don’t use), magnetism