The complete guide
Which jewellery is actually safe to clean ultrasonically
Ultrasonic cleaning is safe for the majority of jewellery — solid gold, silver, platinum, and most cut gemstones like diamonds, sapphires and rubies handle the cavitation process without issue. The exceptions are porous or structurally soft materials: pearls, opals, turquoise and emeralds (which are often treated with oil or resin to fill internal fractures) can be damaged by the vibration or by the cleaning solution stripping their treatment. Coated or plated jewellery is generally fine for occasional cleaning but shouldn't go through daily cycles, since repeated cavitation can gradually wear thin plating. When in doubt about a specific piece, a quick check with a jeweller before its first ultrasonic clean is the safer route.