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The Mohs Scale of Hardness including Birthstones


Birthstones and anniversary gemstones come in differing hardness and this is measured using the Mohs Scale of hardness. We have listed each gemstone next to its relevant hardness.

When choosing a gift with a gemstone make sure it will withstand the wear and tear that it is likely to receive. The softer the gemstone the more likely it is to be damaged. This should not stop you buying things like pearls. The person receiving the gift should be aware that the stone may be damaged by perfume and certain body creams. Gold, silver and platinum may also be discolored by creams.

Mohs Scale Of Hardness

Hardness Damaged by
1. Talc crushable with finger nails
2. Gypsum can be scored with finger nail
3. Calcite, Pearl scored with iron nail
4. Fluorite scored with glass
5. Apatite scored with a penknife
6. Orthoclase feldspar, Opal scored with quartz
6.5 Peridot scored with a file or special steel
7. Quartz, Amethyst, Garnet scored with a file or special steel
7.5 Aquamarine, Emerald only scored by corundum or diamonds
8. Topaz only scored by corundum or diamonds
9. Corundum, Ruby or Sapphire only scored by a diamond
10. Diamond only scored by another diamond

The table shows the Scale of Hardness. It was designed in 1812 by Frederich Mohs, a German mineralogist. Frederich Mohs selected the ten minerals that were common or more readily available back then. This is an arbitrary scale, with very irregular intervals.

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