How to Clean Onyx Jewellery Without Damaging It

Why Onyx Rewards a Gentle Touch

Onyx is a form of chalcedony, a type of quartz with a hardness of roughly 6.5 to 7 on the Mohs scale. That makes it tough enough for an everyday ring or a favourite beaded bracelet, but it is not indestructible. Much of the rich black onyx sold in the UK is chalcedony that has been dyed, and that dye sits within the stone's microscopic pores. Harsh chemicals, heat and overly vigorous cleaning can strip or fade it, leaving a stone that looks tired rather than glossy. Natural banded onyx and sardonyx have their own sensitivities, particularly to acids and sudden changes in temperature.

The reassuring news is that onyx is one of the easiest gemstones to look after. You do not need specialist equipment or expensive products. In most cases, warm water, a mild soap and a soft brush are all it takes to bring back that deep, mirror-like shine.

The Safe Everyday Method

Set aside ten minutes, a small bowl and a soft cloth. This method suits solid onyx set in metal, including rings, pendants, earrings and brooches.

• Use warm, not hot, water. Add a single drop of mild washing-up liquid or baby shampoo. Avoid anything with added moisturisers, antibacterials or grit.
• Soak briefly. Two to five minutes is plenty. This loosens the film of skin oils, hand cream and dust that dulls the surface.
• Brush gently. A baby's toothbrush or a soft make-up brush works beautifully. Pay attention to the underside of the stone, around the claws or bezel, and the gallery beneath the setting, where grime collects unseen.
• Rinse in clean warm water. Do not hold the piece under a running tap, as a loose stone can disappear down the plughole. Swish it in a second bowl instead.
• Dry and buff. Pat with a soft lint-free cloth, then buff lightly with a microfibre cloth to restore the gleam.

If your onyx is strung on elastic or silk thread, skip the soak. Wipe the beads with a barely damp cloth instead, then dry them flat. Repeated soaking weakens cord and elastic, which is a far more common cause of lost beads than dirty stones.

What to Keep Away From Onyx

Knowing what to avoid matters just as much as knowing what to do. The following can dull the polish, remove dye, or loosen a setting:

• Ultrasonic and steam cleaners. The vibrations can shake a stone free from its setting and can worsen any hairline fracture. Steam is worse still for dyed material.
• Ammonia-based silver dips and jewellery cleaners. Ammonia attacks dye and can damage the surface over time.
• Bleach, vinegar, lemon juice, hydrogen peroxide and baking soda pastes. All are either acidic or alkaline enough to affect the stone.
• Acetone, nail varnish remover, alcohol and abrasive toothpaste. Toothpaste is surprisingly scratchy and leaves a hazy finish.
• Household tasks and chemicals. Take rings off before washing up, cleaning the bathroom, gardening or using any spray product.
• Cosmetics and chlorine. Perfume, hairspray, sunscreen, hand cream and swimming pool water all leave a dulling residue or cause fading.

Onyx Set in Silver or Gold

Metal and stone often need different treatment, and it pays to work carefully. A silver polishing cloth is ideal for the metal, but keep the treated side away from the onyx where you can. Cream polishes and dips are best avoided altogether on mixed pieces, as residue settles into the crevices around the setting and is difficult to remove. If you do use a gentle metal polish, apply it with a cotton bud around the stone rather than over it, then rinse the whole piece thoroughly in warm water and dry it well.

Be cautious with glued settings, which appear on some pendants, cufflinks and costume pieces. Soaking can dissolve the adhesive, so clean these with a damp cloth only. Beaded bracelets on silk thread should also be wiped rather than washed, and restrung every year or two if worn often.

Drying, Wearing and Storing

Once clean, let the piece air dry for half an hour before putting it away. Never use a hairdryer, radiator or windowsill to speed things up, as rapid heat changes are unkind to stone and adhesive alike.

As a habit, put your jewellery on last when getting ready and take it off first at night. Store onyx separately in a soft pouch or a lined compartment; harder stones such as diamond, sapphire and quartz will scratch it if they tumble together in a box. Keep dyed pieces out of prolonged direct sunlight, which can gradually fade the colour.

When a Gentle Clean Is Not Enough

Sometimes a stone has a stubborn cloudy patch, a scratch or a white film that will not shift. In these cases, stop rather than escalate. A jeweller or lapidary can re-polish the surface properly and will know whether the setting needs attention too. Faded dyed onyx cannot be revived at home, and DIY dye kits usually make matters worse; a professional can advise on re-dyeing or replacing the stone.

With consistent, gentle care, onyx keeps its depth and gloss for decades. Warm water, a drop of mild soap and a soft brush will do more for it than any gadget on the market.