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Mohs Scale of Hardness
To find the relative hardness of gemstones, jewelers reference this scale.

Scroll to the bottom of the page to find a FREE downloadable PDF of the Mohs Scale of Hardness.

Ametrine gemstone A variety of the quartz family, this ametrine gemstone is a 7 on Mohs Scale of Hardness. For more about ametrine, see Stone Sense in the November 2009 issue of Art Jewelry magazine. As a jewelry maker, knowing the hardness of the gemstones you're working with will help you to design and create more successful jewelry pieces. The harder the gemstone, the more wear it can take; the softer the gemstone, the more you'll want to protect it. While you can safely set a diamond in a claw setting in a ring, you'll want to avoid doing the same thing with much softer apatite. Rings sustain much more daily wear than, say, a pendant or a pair of earrings. Consider a stone's hardness when storing it, deciding how to set it, and working with it.

Mohs Scale of Hardness Talc............................................1 Gypsum....................................2 Calcite.......................................3 Fluorite......................................4 Apatite.......................................5 Orthoclase................................6 Quartz........................................7 Topaz........................................8 Corundum (ruby, sapphire)...9 Diamond.................................10 Commonly, a fingernail is said to have a hardness of 2.5 and a steel file is about 6.5.

Jewelers use Mohs Scale of Hardness (developed in 1812 by Friedrich Mohs) to determine a gemstone's hardness relative to other minerals. According to Richard M. Shull, Art Jewelry magazine's Stone Sense columnist, "A mineral can only be scratched by a harder substance. A hard mineral can scratch a softer mineral, but a soft mineral cannot scratch a harder mineral." The Mohs Scale starts at number 1 with talc, the softest mineral on the scale, and goes to diamond -- the hardest known mineral -- at number 10. "Simply put," says Shull, "the higher the number, the harder the mineral."

Mohs Scale of Hardness File Size: 140 KB

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