Testing Hardness of a Mineral
The hardenss of a mineral is one of the most diagnostic and easy tests to perform in the attempt to indentify an unknown mineral. Hardenss is a measure of a mineral's resistance to abrasion and reflects the atomic structure of a mineral.
Mohs Hardness Scale
Hardness is measured on the Mohs Scale, identified numerically hardness of by standard minerals, from 1 (softest) to 10 (hardest):
A mineral of a given hardenss will scratch a mineral of a lower number. With a systematic approach, you can use minerals of known hardness to determine the relative hardness of any other mineral.