There are beautiful stones beyond number, but setting them in jewelry can be a challenge based solely on the hardness or softness of the stone itself.

The Mohs scale was developed to measure the hardness of stones. Talc or sulfur is a 1 on the scale, meaning they can be easily be scratched with a fingernail.

A diamond is a 10. All other stones fall somewhere in between.

Turquoise is relatively soft at 5-6 on the scale...or can be scratched with a knife. You may have seen turquoise wire-wrapped or bezel set, but probably not prong set, as the prongs may not protect the softer stone sufficiently for normal wear.

Gemstones tend to be harder (they can tolerate faceting): Topaz is an 8, rubies and sapphires are a 9.

The softeness of a stone determines how it is set, but also may limit how it is worn. A fragile stone may work better as a pendant. Hands and arms move around a lot and are more likely to bump into things, so rings and bracelets could be a more dicey choice.

Obviously there are plenty of rings, bracelets, and cuffs made from softer stones, but it is a best practice to let your buyer know that wearing that jewelry for active sports might be a bad idea!

Knowing where your stone falls on the Mohs scale can be valuable information to pass on to your client.

Here's a handy table with some Mohs information. For any particular stone and specific scale (ie, Malachite can fall anywhere between 3-1/3 and 4 on the scale), do an internet search. For example, Mohs Malachite.

Scale Test Material
Mohs Scale
1 Scratches easily with fingernail Talc, Sulphur
2 Can be scratched with a fingernail Amber
3 Can be scratched with a coin (dull metal edge) Coral, Malachite, Pearl
4 Can be scratched easily with a knife Rhodochrosite
5 Can be scratched with a knife Lapis, Opal, Turquoise
6 Can be scratched with a steel file! Stone can scratch glass Labradorite, Moonstone, Peridot, Tanzanite
7 Easily scratches metal, glass, softer stones Amethyst, Citrine, Quartz, Tourmaline, Garnet, Emerald
8 Scratches Stones Mohs 7 and below Topaz
9 Scratches Stones Mohs 8 and below Ruby, Sapphire
10 Scratches Stones Mohs 9 and below Diamond



Post new comment

The content of this field is kept private and will not be shown publicly.
To help us prevent spam, please prove you're human by typing the words you see here.