How durable is your gemstone: “Mohs” the word


Mohs’ Hardness Scale

You probably know that diamonds are one of the hardest gems, but what about other   stones? A stone is a stone, right? But some are more durable than others, and might do better, for example, in a brooch versus an everyday ring. Here’s a quick tutorial.

Gemstones are rated on “Mohs’ Hardness Scale,” from 1 (very soft/can be scratched by a fingernail) to 10 (hard as a diamond). The scale was developed by Friedrich Mohs, a mineralogist who created it in the early 1800s.

Mohs’ Hardness Scale (softest to hardest)

1. Talc / 2. Gypsum / 3. Calcite / 4. Fluorite / 5. Most glass / 6. Feldspar / 7.  Quartz / 8. Topaz / 9. Corundum (ruby, sapphire) / 10. Diamond

Quick facts about gems’ hardness

  • A gem can be scratched by a specimen in a higher rated group. For instance, quartz can be scratched by a topaz. That’s why a diamond can scratch glass.


    Diamonds have a hardness rating of 10

  • Gold, silver, and platinum are relatively soft (with ratings of 1-4). For that reason, they usually contain an amount of other metal when they’re used in jewelry.
  • Quartz, with a rating of 7 is fairly durable for most jewelry. There are many forms of quartz-based gemstones. These include amethyst, citrine, agate, onyx, tiger’s eye, aventurine, jasper, carnelian, and of course, rose, milky, and smoky quartz.
  • Opals rate 5.5 to 6 on the scale, which makes them softer than many other


  • gemstones. If you have an opal ring, consider whether it will stand up to everyday wear, or if it might get scratched.

So, while it may be hard to decide on your favorite jewels and gems, some may actually be harder than others. For information on your gems, including an evaluation of their value, let me know. I’m here to help.

Brilliantly yours,


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