Material reference
Gemstone hardness chart: the Mohs scale
Compare the ten reference minerals and understand what scratch resistance can—and cannot—tell you about a gemstone.
Source-checked reference prepared with AI assistance; independent specialist review pending. Values describe materials, not a certificate for an individual object.
Mohs hardness scale: the reference minerals
The Mohs scale ranks resistance to scratching against reference minerals. The numbers are relative, not evenly spaced. A change of one step does not mean the same increase in measured hardness throughout the scale. See the U.S. National Park Service reference scale and GIA’s durability explanation.
| Mohs rank | Reference mineral |
|---|---|
| 1 | Talc |
| 2 | Gypsum |
| 3 | Calcite |
| 4 | Fluorite |
| 5 | Apatite |
| 6 | Orthoclase feldspar |
| 7 | Quartz |
| 8 | Topaz |
| 9 | Corundum |
| 10 | Diamond |
Common jewelry materials on the Mohs scale
These examples are category-level ranges from GIA. The name, treatments and components of an individual piece still need their own evidence.
| Material | Mohs hardness | Source |
|---|---|---|
| Amethyst (quartz) | 7 | GIA amethyst care |
| Tourmaline | 7–7.5 | GIA tourmaline care |
| Garnet group | 6.5–7.5, depending on type | GIA garnet care |
Where do nephrite and jadeite fit?
GIA lists nephrite at approximately 6–6.5 and jadeite at 6.5–7. These are ranges for material categories, not a way to identify a bracelet from a photograph. Read nephrite versus jadeite for the naming and identification limits. GIA jade care and cleaning gives the ranges and explains how treatments affect care.
Hardness is not toughness
Hardness concerns scratching; toughness concerns resistance to breaking or chipping. GIA also distinguishes stability under heat, light and chemicals. A hard stone may still chip or fracture, and the cord, setting or treatment of an assembled bracelet can change how it should be handled.
A chart does not identify or authenticate a gemstone. Do not scratch a piece of jewelry to test it. Ask a qualified laboratory what an identification report covers and consult the maker about the whole object’s care.
Sources and next steps
- Mohs Hardness Scale — U.S. National Park Service: the ten reference minerals.
- More than the Mohs Scale — GIA: hardness, toughness and stability.
- Jade Care and Cleaning — GIA: jade ranges and care limits.
For a separate question about names and place of origin, read Hetian, Hotan and nephrite.