Minerals are classified according to: Hardness, Specific Gravity (how it compares with the density of water), Color, Luster, Streak, Cleavage and Crystal Form.

The following minerals are categorized according to Hardness. The following chart indicates how you might test a mineral for hardness according to Friedrich Moh's scale. 10 is the hardest, and 1 is the softest mineral. (Links are to photographs of the minerals.)

The number at the left indicates the "hardness" of the mineral. The next column has the object of known hardness that will scratch the representative mineral listed in the last column. The mineral name is linked to a picture of the mineral.

Move your mouse over each name to view the image in a new window. Close the window to view the next image.