The Mohs scale in jewelry: when the hardness of the stone rhymes with durability

Do you want a piece of jewelry that will last a lifetime? Discover the essential tool to choose the perfect stone: the Mohs scale.

Why does the hardness of stones matter in jewelry?

The hardness of a gemstone determines its resistance to scratches, wear and tear and everyday impacts. Indeed, a soft stone risks quickly losing its luster if worn every day, whileA hard stone will retain its beauty and shine for much longer. 

Hardness influences both the storage, maintenance and association of the stones with each otherHere are some concrete examples to better understand the importance of hardness: 

Rings and bracelets, frequently exposed to friction, require very hard stones such as the diamond Or sapphire, whereas a pendant or earrings can accommodate softer stones.

A ruby (Mohs 9) withstands conventional cleaning perfectly, while a turquoise (Mohs 7) must be handled with care and kept away from any abrasive product.

Finally, it is best to avoid storing a soft stone together, such as malachite (Mohs 4) and a hard stone like quartz (Mohs 5-6), otherwise the first one will be scratched.

The Mohs scale: a hardness rating from 1 to 10 

The Mohs scale, invented in 1812 by the German mineralogist Friedrich Mohs, classifies all minerals according to their hardness on a scale of 1 for talc, which crumbles under the fingernail, to 10 for diamond, the hardest mineral in the world. scratchable only by another diamond itself.

Indeed, the'scale is based on the ability of a material (whose hardness is known) to scratch and damage anotherSo, in practical terms, each stone can scratch those of lesser value and be scratched by those of greater value.

In jewelry, this concerns 3 groups of stones: 

• Precious stones : diamond, sapphire, ruby, emerald
• Fine or "semi-precious" stones citrine, amethyst, quartz, topaz, tourmaline, tanzanite, spinel, chrysoberyl...
• Ornamental stones and materials jade, malachite, turquoise, onyx, agate, opal, amber, coral...

Which stones should be chosen for jewelry that is durable enough for everyday wear?

For a piece of jewelry that you want to wear often, or that will be in contact (and subject to friction) with other jewelry, such as a engagement ring for example), it is better to turn to minerals having a hardness of at least 7 on the Mohs scaleHere are some recommendations:

• Diamond (Mohs 10)  The king of durability and brilliance, it is ideal for all types of jewelry and blends perfectly with all other colors of metals and stones.

• Sapphire and Ruby (Mohs 9)  Scratch and shock resistant, these stones are also suitable for all types of jewelry, and are ideal for those who want a touch of color on a daily basis without fear of dulling their shine.

• Topaz And Spinel (Mohs 8)  A good compromise between color, brilliance and robustness, this choice of stones is best suited for rings, earrings or pendants.

• Quartz, Amethyst, Citrine (Mohs 7) Sufficient for necklaces, bracelets, rings, to be avoided for manual professions - or prefer to remove them to prevent possible scratches.

• Opalturquoise, lapis lazuli (Mohs 5 to 6)  Opaque stones with very pronounced and vibrant colours, but more fragile, to be worn occasionally, or opt for a jewellery setting that will protect them best. 

Be careful though, because some stones, like theemerald (Mohs 7.5-8), while possessing good hardness, are prone to chipping due to numerous internal inclusions: therefore, avoid impacts even with a stone considered hard. all the chemical and physical characteristics of a stone have their role to play.

Summary table of stone hardness