Mohs Hardness Scale
The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
The table below shows the hardness for various gemstones.
Rating | Test Rock | Other Tests |
---|---|---|
1 | Talc | Can be scratched by fingernail |
2 | Gypsum | Scratched by copper/bronze coin |
3 | Calcite | Scratched by copper/bronze coin |
4 | Fluorite | Scratched by steel; scratches coin |
5 | Apatite | Scratched by steel; scratches coin |
6 | Feldspar | Scratches glass |
7 | Quartz | Not scratched by steel |
8 | Topaz | Not scratched by steel |
9 | Corundum | Not scratched by steel |
10 | Diamond | No mineral harder |
The table below shows the hardness for various gemstones.
Gemstone | Hardness |
---|---|
Serpentine | 1.5 |
Amber | 2-2.5 |
Chrysocolla | 2-2.5 |
Tortoise shell | 2.5 |
Pearl | 2.5-3.5 |
Jet | 2.5-4 |
Coral | 3.5 |
Rhodochrosite | 3.5-4.5 |
Rock crystal | 3.5-5 |
Lapis Lazuli | 5.5 |
Moonstone | 5.5-6 |
Turquoise | 5.5-6 |
Opal | 5.5-6.5 |
Tanzanite | 6 |
Chalcedony | 6.5-7 |
Jade | 6.5-7 |
Peridot | 6.5-7 |
Garnet | 6.5-7.5 |
Kunzite | 7 |
Quartz | 7 |
Tourmaline | 7-7.5 |
Zircon | 7.5 |
Beryl | 7.5-8 |
Spinel | 8 |
Topaz | 8 |
Chrysoberyl | 8.5 |
Sapphire | 9 |
Ruby | 9 |
Diamond | 10 |
Source: Wikipedia, Dragon #248
Comments