A guest leaves a diamond ring on the vanity and mentions, on the way out, that it "looks a bit cloudy". There is an ultrasonic cleaner in the crew mess that somebody bought in Palma. You could hand the ring back sparkling in ten minutes. You could also, in the same ten minutes, loosen four stones and destroy an emerald. Here is the line you never cross.
What you may do
Almost nothing, and that is deliberate.
- A soft, dry, clean cloth — a fresh microfibre or a jeweller's cloth — lightly wiped over a hard metal or diamond piece.
- Nothing else, ever, without a specific instruction from the chief stew or the guest.
That is the whole permitted toolkit. Cleaning fine jewellery properly is a job for a jeweller, and every shortcut in the crew mess has a graveyard behind it.
The hard rules
Never use any of these on a guest's jewellery:
- Ultrasonic cleaners — they loosen settings, shake out stones, and shatter emeralds and any fracture-filled or treated stone.
- Steam cleaners and hot water — heat cracks opals and drives oil out of emeralds.
- Ammonia, bleach, chlorine — attack gold alloys, strip rhodium plating, and destroy pearls.
- Solvents, acetone, alcohol — dissolve glues in costume and vintage pieces and damage porous stones.
- Toothpaste, baking soda, polishing compound — abrasive; they put permanent micro-scratches into soft metals and pearls.
The fragile three, and hardness
| Stone | Mohs hardness | The specific hazard |
|---|---|---|
| Diamond | 10 | Scratches every other stone and metal in the box |
| Ruby / sapphire | 9 | Hard, but settings still work loose |
| Emerald | 7.5–8 | Brittle, usually oil or resin filled; ultrasonic and heat ruin it |
| Pearl | 2.5–4.5 | Organic nacre; destroyed by acids, perfume, hairspray, sweat and dryness |
| Opal | 5.5–6.5 | Contains water; crazes with heat, dry air and solvents |
Pearls are last on and first off — perfume and hairspray go on before the pearls, never after. Store pieces separately, each in its own pouch or compartment. A diamond loose in a tray with a pearl necklace is a slow-motion accident.
Settings, clasps and the loose stone
Every time you handle a piece, look and listen. A stone that rattles or clicks, a claw that has bent, a clasp that no longer springs shut — these are findings you report, immediately, in writing. You never tighten, glue, bend or "test" a setting. If a stone comes out in your hand, you stop, you keep everything including the stone, and you go straight to the chief stew with a witness.
Onboard Notes
- Soft dry cloth. That is the entire list of what you may do unasked.
- No ultrasonic, no steam, no ammonia, no solvent, no toothpaste. Ever.
- Pearls, opals and emeralds are ruined by things that look harmless.
- A loose stone is reported in the same minute you notice it — not later.