Opal is the stone most often ruined by cleaning, and the reason is that almost every general jewellery-cleaning instruction is wrong for it. Opal contains water — between 3% and 20% by weight — and most of what damages it comes down to that.
The short version
Lukewarm water, a drop of mild soap, a soft cloth. Nothing else. No ultrasonic cleaner, no steam, no silver dip, no ammonia, and never soak a doublet or triplet — water gets between the layers and clouds them permanently.
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First: which kind of opal do you have?
This decides everything, and most people do not know.
Solid opal is one piece of stone. It can be gently wiped with water without harm.
A doublet is a thin slice of opal glued to a dark backing. A triplet adds a clear quartz or glass cap on top. Both are common in affordable jewellery and both are held together with adhesive.
How to tell: look at the stone from the side. A doublet or triplet shows a straight, sharp line where the layers meet; a solid opal has no such line and the colour continues round the curve. The line can be very fine, and a 30x loupe with a light, around $23, settles it in seconds. Given that getting this wrong destroys the stone, it is worth the certainty.
If it is a doublet or triplet, never submerge it. Water seeps into the glue line by capillary action, and the stone develops a grey cloudy patch that cannot be removed. This is the single most common way opal jewellery is destroyed, and it happens in seconds.
How to clean it
Dampen a soft cloth or a cotton bud in lukewarm water with the smallest amount of mild washing-up liquid. Wipe the stone. Wipe again with a cloth dampened in clean water. Dry immediately with a soft dry cloth.
That is the whole procedure. Solid opal can be briefly rinsed under a lukewarm tap if it is genuinely dirty. Doublets and triplets never go near running water.
For the metal around the stone, use a silver polishing cloth, around $14, and keep it off the opal itself — polishing compounds are mildly abrasive and opal is soft, around 5.5 to 6.5 on the Mohs scale, softer than window glass.
What destroys opal
Ultrasonic cleaners. The vibration can crack solid opal along internal fault lines and will separate a doublet outright. Jewellers keep opal out of the tank as a rule.
Steam cleaners. Heat plus moisture is the worst combination for a hydrated stone.
Silver dip and ammonia-based cleaners. They attack the stone as well as the tarnish, leaving the surface etched and dull.
Sudden temperature change. Hot water on a cold stone can cause crazing — a network of fine internal cracks that is permanent and, once started, tends to spread.
Very dry storage. Long periods in a safe or a heated room can dehydrate solid opal and cause the same crazing. If a piece is stored for years rather than months, a small damp cotton pad in the box — not touching the stone — helps.
Wearing it
Take opal off before swimming, showering, cleaning and gardening. Chlorine and household cleaners are both bad, and it is soft enough to scratch against almost anything.
Put it on last, after perfume, hairspray and lotion. Opal is porous and absorbs oils, which dull it over time and cannot be cleaned back out.
If it has gone cloudy already
A doublet or triplet with water between the layers cannot be fixed at home, and usually not at all — the only route is having the stone reset, which costs more than most affordable opal pieces are worth.
A solid opal that looks dull is often just coated in skin oils and soap film, and the gentle clean above will bring it back. If it is crazed, with visible fine cracks, that is structural and permanent.
Related
Our opal collection includes turtle, dolphin and elephant pieces, most set as solid stones. For the metal side of things, cleaning tarnished silver covers what is safe on plated settings.
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