Exotic Inlay Materials
For woodworkers, turners, casters, luthiers, jewelers, crafters, professionals and hobbyists

Mohs Hardness Scale

 

Mohs scale of mineral hardness is named after the scientist, Friedrich Mohs, who invented a scale of hardness based on the ability of one mineral to scratch another. Rocks are made up of one or more minerals.

 

According to the scale, Talc is the softest: it can be scratched by all other materials. Gypsum is harder: it can scratch talc but not calcite, which is even harder. The hardness of a mineral is mainly controlled by the strength of the bonding between the atoms and partly by the size of the atoms. It is a measure of the resistance of the mineral to scratching.

 

Our opals have a hardness of 4 and are easily sanded using silicon carbine (carborundum) or aluminum oxide (corundum) sand paper, which has a hardness of 9.0. They are durable and provide an excellent surface to polish and/or finish. Available in nine colors: Marina (blue); Viper (green); Krakatoa (light gray), Confetti (purple), Dragon's Eye (red), Marianas (dark blue), Moonbeam (white), Sahara (yellow), and Shadow (dark gray).