Wavy Diamond Heart Hoop Earrings in 18K recycled gold with natural diamonds, hardness guide for everyday New York wear

How Hard Is a Diamond? A Scientific Guide to Hardness in Gems and Metals

Diamond is a 10 on the Mohs hardness scale, the hardest natural material known, while pure gold sits at only about 2.5 to 3. That contrast explains almost everything about how fine jewelry wears: diamonds resist scratches, gold takes small marks over time, and neither is indestructible. If you wear your pieces every day in New York, a little materials science goes a long way.

What is the Mohs scale?

In 1812 the German mineralogist Friedrich Mohs ranked minerals by a simple test: which one can scratch which. Talc is 1, diamond is 10. The scale is ordinal, so the steps are not equal. Diamond is far harder than corundum at 9, much more than one step's worth.

Where do jewelry materials sit?

  • Diamond: 10
  • Sapphire and ruby (corundum): 9
  • Emerald: about 7.5 to 8
  • Quartz, including citrine and amethyst: 7
  • Platinum: about 4 to 4.5
  • Pearl: about 2.5 to 4.5
  • Gold: about 2.5 to 3

Everyday dust contains tiny quartz particles at 7, which is why softer stones and metals slowly lose their polish while diamond stays crisp.

Wavy Diamond Stud Earrings, a small diamond wave in 18K recycled gold

Is hardness the same as toughness?

No, and this is the part most people miss. Hardness is resistance to scratching. Toughness is resistance to breaking or chipping. Diamond's carbon atoms are bonded so strongly that nothing natural scratches it, but the crystal has cleavage planes, directions along which a sharp knock can split it. That is why a well designed setting protects the stone's edges. Emerald is harder than gold yet more brittle than diamond, and gold is soft but very tough: it bends rather than breaks.

How does alloying change gold?

Pure 24K gold is too soft for rings that live on a busy hand. Adding silver, copper and other metals makes it harder. 18K gold, which is 75% gold, is noticeably stronger than pure gold and keeps a deep color. 14K is harder again. The Wavy pieces are made in 18K recycled gold, a balance between richness and everyday durability, as in the Wavy Diamond Heart Hoop Earrings and the Wavy Diamond Stud Earrings.

Two gold diamond bangles stacked on the wrist

What does this mean for daily care?

  • Store diamond pieces apart from plain gold, because diamond will scratch gold.
  • Take rings off for the gym and heavy lifting, where a knock can stress a setting.
  • Clean gently with warm water, mild soap and a soft brush.
  • Have prongs and settings checked every few months on pieces you wear daily.

For the full routine, see how to clean gold and diamond jewelry at home. Margaret Krinetz Fine Jewelry, handmade in Tel Aviv and shipped to New York, designs every setting to protect its stones.

Frequently asked questions

Can a diamond break?

Yes. It cannot be scratched by anything natural, but a hard knock at the wrong angle can chip it.

Is 18K gold strong enough for everyday wear?

Yes. It is alloyed for strength and suits daily jewelry with sensible care.

How long does delivery to New York take?

Every piece is made to order in 4 to 6 weeks and ships with DHL Express in 3 to 5 business days. Shipping is free on orders over $1,500.

Questions about a stone or a setting? Write to me.

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