Gemstone Care and Cleaning by Stone Type
What is safe in an ultrasonic cleaner, why treated and fractured stones need different handling, and how to store stones without scratching.
Most gemstones are cleaned the same way, with lukewarm water, a drop of mild dish soap, and a soft brush, and the exceptions are where stones get ruined.
The default method
Use lukewarm water, not hot. Add a small amount of mild dish soap. Brush gently with a soft-bristled brush, rinse in clean lukewarm water, and dry with a lint-free cloth. A baby toothbrush works well because the bristles are soft and the head is small enough to reach under a setting.
This method is safe for diamond, corundum, quartz, spinel, garnet, and beryl that carries no filling. Everything below is an exception to it.
Never in an ultrasonic cleaner
An ultrasonic cleaner works by vibration in a liquid, which is effective on hard, untreated stones and risky for many others. Keep these out of it:
- Emerald, and any stone treated by oiling or resin filling. The filler can be vibrated or dissolved out.
- Any fracture-filled stone, including glass-filled ruby. The filling can be damaged or removed.
- Opal, which contains water and can fracture under vibration or heat.
- Tanzanite, which has one cleavage direction and a reputation for being heat-sensitive.
- Turquoise, lapis lazuli, malachite, and dyed stones, all of which are porous or dyed, and some of which are damaged by water or acids.
- Pearls, coral, amber, and shell, which are organic or soft materials that solvents and vibration will degrade.
- Moonstone and other feldspars with cleavage.
- Any stone you cannot identify, and any stone glued into a setting rather than held by metal.
Steam cleaners carry most of the same warnings, with the addition that heat will damage opal and can harm treated stones.
Chemicals worth avoiding
Ammonia-based cleaners are common for gold and platinum and are unkind to pearls, turquoise, opal, and dyed material. Silver polish contains abrasives and chemicals that should not contact soft stones at all, so polish silver with the stone masked or removed. Chlorine in pools and hot tubs attacks metal alloys and can dull or etch some stones. Perfume, hairspray, sunscreen, and lotion leave films that dull a stone's surface, so jewelry goes on last and comes off first.
Storage that prevents scratching
Quartz sits at Mohs 7, and quartz dust is a common abrasive, so soft stones stored loose with hard ones will pick up scratches over time.
- Give each stone its own soft pouch or its own compartment. Do not let stones touch.
- Keep harder stones apart from softer ones even inside a compartmented tray.
- Keep pearls and opals in a soft pouch rather than on a hard surface, and give them moderate, stable conditions away from dry heat.
- Avoid hanging pendants so that stones rest against each other.
- Store away from direct sunlight if the collection includes amethyst, kunzite, rose quartz, or dyed material, all of which can fade over long exposure.
Opal deserves one specific note: it should not be soaked, oiled, or subjected to sudden temperature changes, because it holds water within its structure. A soft pouch and normal indoor conditions are the right answer.
Wear habits
Take rings off for housework, gardening, dishes, and the gym. Check prongs once a year, and have any loose stone tightened before it drops out. If a stone feels rough along a facet edge, that is a chip, and it is worth looking at sooner rather than later.
Clean with lukewarm water and mild soap unless the stone is on the exception list, and when you are unsure what a stone is, use a dry soft cloth and nothing else.
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