A jeweller in Mumbai's Zaveri Bazaar keeps a small ultrasonic cleaner behind the counter. Every customer who brings in a piece of jewellery, whether for repair, resizing, or just evaluation, has it cleaned before they look at it together. The difference between a diamond before and after that cleaning is sometimes startling. A stone that looked like it needed replacing in the setting turns out to be a fine diamond that simply hadn't been cleaned in two years. The oil from daily skin contact is transparent individually but accumulates into a film that catches light like frosted glass rather than reflecting it like a mirror. Most diamonds that "look dull" are dirty.

Why diamonds get dull: the chemistry of build-up

The human skin produces sebum (a natural oil) continuously. Every time a ring touches the skin it picks up a microscopic layer. Soaps and detergents leave residue on stones after rinsing. Hand creams and moisturisers coat the back of a stone particularly, the area between the pavilion facets and the setting where the cream accumulates and is never touched. Cosmetics, perfume, and hairspray all deposit residue. Each layer individually is barely perceptible. After weeks of daily wear, the accumulated film on the pavilion of a diamond significantly reduces the light entering from underneath, which is the primary driver of a diamond's brilliance. Cleaning removes this film and restores the optical path.

At-home cleaning: the standard method

The standard at-home method is warm water and mild dish detergent. Fill a small bowl with warm (not hot) water, add two or three drops of mild dish detergent, and soak the piece for 20-30 minutes. Then use a soft-bristled toothbrush (new, used only for jewellery) to gently scrub the stone and setting, paying particular attention to the back of the stone and around the prongs and between the setting components where oil accumulates most. Rinse thoroughly under warm running water, with the drain closed or a strainer in place, since a ring dropped in a sink is frequently lost. Pat dry with a lint-free cloth (microfibre is ideal). The entire process takes under five minutes and should be done every 2-4 weeks for daily-wear rings (GIA consumer care guidance).

Ultrasonic cleaners: when to use and when not to

Ultrasonic cleaners use high-frequency sound waves in a liquid bath to dislodge dirt. They are highly effective for diamonds in secure, well-maintained prong or bezel settings. They should NOT be used for: fracture-filled diamonds (the vibration can dislodge the filler), emeralds in any setting (virtually all emeralds are oiled, the ultrasonic can remove the oil and change the stone's appearance), pearls (the nacre can be damaged), opals, turquoise, coral, amber, or any other porous or delicate gem. When in doubt, use the warm water method. If your setting has any loose prongs, ultrasonic cleaning can cause a stone to fall out of the setting, check prong integrity before using an ultrasonic (GIA; jewellery care professional guidance).

Professional cleaning and prong inspection: the annual check

Take diamond jewellery to a reputable jeweller for professional cleaning and a prong inspection once or twice a year. The prong inspection is the most critical maintenance step. Prongs are the thin metal claw-like structures that hold the diamond in its setting. They are subject to constant wear from daily contact with surfaces, and over years they wear, bend, or break. A prong that has worn thin can allow a diamond to shift or fall out, and diamonds do fall out of rings, most often in the shower or while removing gloves. A jeweller can check prong integrity, retip worn prongs, tighten loose settings, and polish the metal to restore its finish. This service is typically free or very low cost from the jeweller who made the piece. Do not wait until a prong visibly breaks (GIA; professional jewellers).

Safe storage: the scratching risk

Diamond (Mohs 10) will scratch every other gemstone and most metals. Store diamond jewellery separately from other pieces, in individual fabric pouches, separate compartments in a jewellery box, or individual soft bags. Never store multiple diamond pieces loose in the same container where they can contact each other (diamonds can scratch each other's settings and other gems in adjacent pieces). The most common damage to fine gemstones in jewellery collections comes not from wear but from improper storage where pieces contact each other (GIA).

What to avoid in daily wear

Remove diamond rings before: heavy manual work (prongs catch on materials and can bend or break), gardening (contact with abrasive soil wears prongs and metal), swimming in chlorinated pools (chlorine attacks gold alloys over time, degrading the metal integrity), exercising with equipment (gym equipment is rough on fine settings), sleeping (the mattress and bedding fabric constantly stress prongs during sleep). These are habits rather than absolute rules, diamonds are durable and will survive most daily contact, but consistently following them extends the time between professional repairs significantly and protects the setting's long-term integrity (GIA; jewellery professional guidance).

Sources

  • GIA. Consumer care and cleaning guidance. gia.edu.
  • GIA Gem Reference Guide. (2006). Gemological Institute of America.