Jewellery Care & the Mohs Scale
Most jewellery is ruined not by wear but by the wrong clean. The trick is knowing how hard — and how delicate — your stones are. That's what the Mohs scale tells you.
The Mohs hardness scale
Mohs ranks a mineral's resistance to scratching from 1 (talc) to 10 (diamond). Everyday dust and grit sit around 7, so stones above 7 shrug off daily scratches — softer ones need protecting.
Everyday cleaning
For most hard gemstones set in gold or platinum, you need nothing fancy: warm water, a drop of mild dish soap, and a soft toothbrush. Brush gently — especially behind the stone, where grime dulls sparkle — then rinse and pat dry. Do it over a bowl, not an open drain.
What to keep away
- Chlorine & bleach. They attack gold alloys and weaken the prongs holding a stone — take rings off before pools, hot tubs, and cleaning.
- Ultrasonic & steam cleaners. Fine for untreated diamond, sapphire and ruby — but they can shatter or dull emerald, opal, pearl, turquoise, amber and fracture-filled stones. When in doubt, don't.
- Perfume, lotion, hairspray. Cosmetics film over stones and eat at pearls and opals. Jewellery goes on last.
- Loose storage. Diamonds scratch everything — and harder stones scratch softer ones. Keep pieces apart.
Pearls & soft stones
Pearls, coral and amber are organic and soft — never soak or ultrasonic them. Wipe a pearl with a damp soft cloth after wearing, and remember "last on, first off": put pearls on after perfume and make-up, take them off first. Strung pearls should be re-knotted every few years, as the silk stretches and weakens.
General guidance, not a substitute for a jeweller's advice on a specific piece — treated and antique stones can need special handling.