Jewellery gets grubby. Hand cream, soap residue, hairspray and natural oils collect behind stones and inside the links of a chain, and a ring that once sparkled starts to look flat and grey. Cleaning it is a sensible habit. The trouble is that the methods people reach for first are often the ones that do the most damage. A few seconds of thermal shock can craze an opal, and one cycle in an ultrasonic tank can wreck a fracture-filled emerald. Here is what to avoid, and what to do instead.
Start with what the stone can take
Hardness and treatment matter far more than appearance. On the Mohs scale, diamond sits at 10 and will shrug off a soft brush; a pearl, at roughly 2.5 to 4.5, will not. Most gemstones sit somewhere between, and plenty of them scratch, discolour or crack when handled like a diamond.
Treatments complicate things further. Emeralds are commonly filled with oil or resin to disguise fractures, so anything that dissolves or heats that filler — solvents, steam, ultrasonic vibration — changes how the stone looks for good. Many rubies and sapphires are heat-treated, which is stable, but glass-filled stones are not. If you don't know a piece's history, treat it as delicate.
Stones to handle with care
- Pearls, coral and amber — soft, and damaged by acids, alcohol and perfume
- Opal — sensitive to heat, dryness and sudden temperature change
- Turquoise, lapis lazuli and malachite — porous, and easily discoloured by chemicals
- Emerald — usually fracture-filled; never ultrasonic or steam
- Tanzanite, kunzite, apatite and moonstone — soft, with cleavages that can split
Mistake one: reaching for the ultrasonic cleaner
Ultrasonic tanks are brilliant for the right job. A diamond solitaire in a sturdy setting, a plain gold band, a sapphire with no fractures — these come out spotless, including the grime behind the stone that no brush can reach.
They are the wrong tool for a long list of pieces. Vibration and cleaning solution will open existing fractures, loosen filler in emeralds, cloud opals and shift glue in settings that were assembled with adhesive. It can also shake a prong that was already weak, so the stone works loose days later. If a piece contains a pearl, opal, emerald, turquoise or any glued element, keep it out of the tank.
Mistake two: harsh chemicals and household cleaners
Bleach and chlorine are the worst offenders. They attack the alloy in gold jewellery over time, making it brittle, and they are ruinous for silk thread and elastic. The practical rule is simple: take rings and bracelets off before you clean the bathroom, visit the swimming pool or sit in a hot tub.
Other everyday culprits include nail polish remover, which damages amber and some treated surfaces; ammonia, which is fine for diamond and gold but not for pearls, opals or porous stones; and vinegar or lemon juice, which will slowly etch softer stones and dull a polished finish. Silver dip works fast on tarnish, but its acids are unkind to gemstones and will strip the deliberate oxidised finish on antique-style silver settings.
Mistake three: heat, steam and sudden temperature changes
Thermal shock is the quiet killer. Run a cold opal under hot water and the internal stresses can craze it — a network of fine cracks that shows up as cloudiness and never goes away. Amber softens and can slump; wax or resin fillers sweat out of fractures; glued settings let go.
Steam cleaners combine heat with pressure, pushing moisture into cracks that were invisible before. Boiling water and hairdryers do the same job more slowly. Keep cleaning water lukewarm, and if a stone feels warm to the touch when you have finished, the water was too hot.
Mistake four: abrasive pastes and rough cloths
Toothpaste is the most common one. It is a mild abrasive designed for tooth enamel, and it will take the shine off gold, scratch softer stones and leave a dull film on the metal around them. So will bicarbonate of soda, whitening powders and any scratch remover intended for metal.
Drying materials matter too. Kitchen roll, tissues and paper towels have wood fibres that leave fine scratches on polished surfaces over time. Use a lint-free jewellery cloth or a microfibre cloth instead. If you do use a toothbrush, choose a soft one and keep it for jewellery only — a stiff brush catches prongs and can chip a stone at the girdle.
Mistake five: soaking things that should stay dry
Soaking gets recommended a lot, and for a diamond ring in a bowl of soapy water it is fine. For a knotted strand of pearls or beads, it is not. Water weakens and stretches the silk or nylon thread, and soap residue left inside the knotting turns sticky and attracts more dirt. Porous stones such as turquoise and lapis will drink the soapy water and discolour from within.
Two smaller habits worth breaking: cleaning over an open plug hole, and storing jewellery damp. Work over a bowl, or a sink with the plug in, and let pieces dry completely — particularly behind the stone and in the joins of a chain — before they go back in the box.
A safe routine for almost any piece
If you are unsure about a stone, this method is gentle enough for most jewellery and effective on everyday grime.
- Check the setting first. Look at the prongs under a bright light. If a stone moves or a claw is worn, stop and take it to a jeweller.
- Fill a small bowl with lukewarm water and a drop of mild washing-up liquid. Work over the bowl, never over an open drain.
- Soak hard stones such as diamond, sapphire and ruby for a few minutes. Skip this step for pearls, opals, emeralds, amber and porous stones.
- Brush gently with a soft brush, working around the setting rather than across the face of the stone. A cocktail stick is useful for reaching behind a stone.
- Rinse in clean lukewarm water of the same temperature, then pat dry with a soft lint-free cloth.
- For pearls, use a damp cloth and dry immediately. No soaking, no chemicals, and have a frequently worn strand restrung before the thread stretches.
- Leave pieces to air dry fully before storing them separately in soft pouches, so harder stones cannot scratch softer ones.
Some jobs are worth handing over. Antique pieces, invisibly set stones, anything with a gem you cannot identify, and jewellery that has been in the family for decades all benefit from a professional clean — a jeweller can check the settings at the same time and tell you what you actually own. If a stone looks cloudier after you have cleaned it, stop and get advice rather than trying again; some damage cannot be reversed.
