Comment nettoyer une pierre precieuse a la maison?

Eau tiede, savon doux et brosse souple, une fois par mois. On laisse tremper quelques minutes, on brosse doucement le dessous de la pierre ou la poussiere s'accumule, on rince a l'eau claire et on seche sur un chiffon non pelucheux. Cette methode convient a toutes les familles sans exception.

Peut-on nettoyer une emeraude aux ultrasons?

Non, jamais — ni ultrasons ni vapeur. La quasi-totalite des emeraudes recoit une huile incolore qui ameliore la lisibilite du vert : les ultrasons et la chaleur l'expulsent, et la pierre perd en transparence. L'entretien se fait a l'eau tiede et au savon doux, et l'atelier peut raviver l'huilage au fil des annees.

Quelles pierres supportent les ultrasons?

Les corindons — saphir et rubis — et le spinelle les supportent sur une pierre saine, c'est-a-dire sans inclusion debouchant en surface ni fissure. Nous les pratiquons en atelier, ou l'etat de la gemme est verifie avant. Une pierre incluse, une emeraude ou une tanzanite ne doivent jamais y passer.

Comment ranger ses bijoux en pierres de couleur?

Separement, chacun dans sa pochette ou son compartiment. La raison est simple : la durete n'est pas la meme d'une famille a l'autre, et le corindon raye toutes les autres pierres. Un saphir et une tourmaline qui voyagent ensemble dans la meme boite finissent par abimer la plus tendre des deux.

Quand faut-il retirer sa bague?

Pour le sport de contact, le jardinage, la salle de sport, les produits menagers et la piscine. Pour une emeraude, on ajoute la vaisselle, la plage et tout travail manuel. Le risque principal n'est pas la rayure mais le choc sur une griffe, qui desserre le sertissage sans qu'on s'en apercoive.

A quelle frequence faire controler le sertissage?

Tous les deux ans, ou immediatement apres un choc important. Chez Bonnot Paris, ce controle est offert a vie. Une griffe qui joue se resserre en quelques minutes ; une pierre perdue ne se remplace jamais a l'identique.

Que faire si la bague a perdu son eclat?

Dans la plupart des cas, ce n'est pas la pierre mais le metal : l'or blanc est rhodie, et cette couche de surface s'use en deux a trois ans. Un rhodiage lui rend sa blancheur. Si c'est la pierre qui parait terne apres nettoyage, il faut regarder le dessous de la monture, ou un film de savon et de poussiere s'accumule.

Back

How to Clean Your Precious Stones: A Care Guide for Radiant Jewellery

Bonnot Paris

April 29, 2026

5 min read

Bonnot Paris · The Precious Stone Journal 2026

How to clean your precious stones

Lukewarm water, mild soap, a soft brush — and a few absolute prohibitions. The protocol, family by family, and what belongs in the workshop rather than the bathroom.

By François Deprez, founder · Care · 7 min · September 2026

A stone almost never gets dirty. It is the underside of the setting that becomes clogged — and that is where the loss of brilliance attributed to the gem comes from.

Light enters through the top of a cut stone, reflects off the pavilion facets and exits through the table. If a film of soap, cream and dust forms beneath the setting, some of this light no longer escapes. The stone appears lifeless even though it is intact.

Hence this principle, which can be summed up in one line: a ring is cleaned from underneath. The rest of this guide explains what to use, how often, and above all what you should never attempt — because when it comes to care, damage almost always comes from excessive zeal.

Ring set with a pink sapphire, placed after cleaning — Bonnot Paris — A clean ring shines not because the stone has been polished, but because light can once again pass through the pavilion from end to end.

It is suitable for all families without exception, including the most delicate. Once a month is enough for a ring worn every day.

Soak

For a few minutes in lukewarm water — never hot — with a drop of mild soap.

Brush underneath

Use a soft-bristled brush, paying particular attention beneath the setting and between the prongs. Do not press.

Rinse

With clear lukewarm water. Plug the sink before you begin — it is the most useful advice in this article.

Dry

On a lint-free cloth, without rubbing. Allow to dry completely before storing.

The real enemy

It is neither dust nor soap, but creams and body oils. They form a film that traps everything else. A ring removed before applying hand cream stays clean three times longer.

Beyond the basic method, gemstones fall into three groups. The dividing line is not hardness, but the presence or absence of a fragile treatment and fractures reaching the surface.

Rectangular teal sapphire platinum engagement ring, baguette diamonds — Bonnot Paris

Regime 1 · the most flexible

Corundum

Sapphire and ruby, hardness 9. Lukewarm water and mild soap for daily care; ultrasonic cleaning is possible in the workshop on a sound stone.

View sapphire rings →

Regime 1 · untreated

Spinel

Hardness 8 and almost never treated: nothing to spare, no oil to preserve. The same care as corundum.

View spinel rings →

Regime 3 · the strictest

Emerald

Oiled in almost all cases. No ultrasonic cleaning, steam or hot water: the oil would dissipate and the green would lose clarity.

View emerald rings →

Regime 2 includes sound but softer stones — tourmaline, garnet — detailed in the table below.

Family	Hardness	Care	Ultrasonic cleaning
Sapphire, ruby	9	Lukewarm water, mild soap, soft brush.	Possible in the workshop
Spinel	8	Same as corundum. Generally no treatment to spare.	Possible in the workshop
Emerald	7,5 – 8	Lukewarm water and mild soap only, gentle cleaning.	Never
Aquamarine	7,5 – 8	Lukewarm water and a soft brush. Same mineral family as emerald, but rarely oiled.	To be avoided
Tourmaline, garnet	7 – 7,5	Lukewarm water and a soft brush. Avoid thermal shock.	Avoid
Tanzanite	6,5	Sensitive stone: gentle cleaning only, and a protective setting.	Never

An important distinction regarding corundums. A sapphire engagement ring or a ruby engagement ring can withstand ultrasound — but only on a sound stone, meaning without any surface-reaching inclusion or crack. This is exactly what we check before putting them through the machine in the workshop, and why we advise against domestic devices: nothing tells you what condition your gemstone is in.

At the other end of the spectrum, an emerald engagement ring must never go near one. And in between, a spinel engagement ring behaves like a corundum: since spinel is almost never treated, there is no oil or filling to preserve.

We see a few care-related accidents every year. They all look alike.

To avoid	Why
Steam	Heat and pressure: it drives the oil out of an emerald and weakens any included stone.
Domestic ultrasonic cleaners	Without first checking the condition of the gemstone, they widen existing cracks.
Bleach and chlorine	They attack gold alloys and can alter certain stones. So can the swimming pool.
Household cleaning products	Too harsh for metal, and often abrasive. Mild soap is enough.
Abrasive pastes	Toothpaste, bicarbonate of soda, powders: they irreversibly scratch polished metal.
Boiling water	Thermal shock can shatter an included stone. Lukewarm means lukewarm.

The habit that saves the most rings

Remove your ring for sport, gardening, housework and swimming. The main risk is not scratching: it is impact on a prong, which loosens the setting without anything being visible. The stone still holds for a few weeks, then it falls out.

This is the least-known and most useful rule: each piece of jewellery in its own pouch or compartment. The reason can be summed up in one sentence — hardness varies from one family to another, and corundum scratches all other stones.

Loose coloured gemstones, from different families and with different hardnesses — Bonnot Paris — Sapphire, tourmaline, garnet, spinel: four different hardnesses. Stored together, the hardest damages the softest — and it is irreversible.

The Mohs scale is a scratch scale, not a measure of toughness: a sapphire at 9 scratches a tourmaline at 7, and diamond scratches them all. A sapphire ring and a tanzanite pendant travelling together in the same pouch will end up marking each other — the metal first, then the softer stone.

When travelling, the same rule applies even more strictly: individual pouches, in the cabin rather than in checked luggage, and the ring on your finger rather than in a bag.

Three procedures should not be carried out at home, and two of them are complimentary with us.

Inspection and adjustment of a ring at the workbench — Bonnot Paris — A loose prong can be tightened in a few minutes at the workbench. A lost stone, however, can never be replaced identically.

Setting inspection, every two years or after a significant impact. It is the only truly essential procedure, and it is complimentary for life on our creations. We check the play in the prongs, wear on the underside of the shank and the stone’s tension in its setting.

Rhodium plating, for white gold only. Rhodium is a surface layer that wears away within two to three years: when the ring takes on a yellow-grey hue, it is not the stone that has dulled, but the metal reappearing. Platinum, on the other hand, requires nothing — it is naturally white.

Refreshing the oil treatment, for emeralds. Over the years, the colourless oil evaporates and the stone’s garden becomes more visible. The workshop can repeat the process: it is routine care, not a repair.

The sign that should alert you

If you hear or feel the stone move slightly when you tap the ring near your ear, stop wearing the piece and have it inspected. It is the only reliable symptom of a setting that has become loose. Book an appointment →

How do you clean a stone at home?

Lukewarm water, mild soap, a soft brush, once a month. Soak for a few minutes, gently brush beneath the stone where dust accumulates, rinse with clean water and dry on a lint-free cloth. This method is suitable for every family, without exception.

Can an emerald be cleaned with ultrasounds?

No, never — neither ultrasound nor steam. Almost all emeralds receive a colourless oil that improves the clarity of their green: ultrasound and heat expel it. The workshop can refresh the oiling over the years, but it is better not to have to do so.

Which stones can withstand ultrasound?

Corundums — sapphire and ruby — and spinel, provided the stone is sound, with no surface-reaching inclusions or cracks. We use them in the workshop, where the condition of the gemstone is checked beforehand. An emerald or a tanzanite must never undergo this treatment.

How should jewellery be stored?

Separately, each in its own pouch or compartment. Hardness varies from one family to another, and corundum scratches all other stones: a sapphire and a tourmaline stored together will eventually damage the softer of the two.

When should you remove your ring?

For contact sports, gardening, the gym, household products and the swimming pool. For an emerald, add washing-up, the beach and any manual work. The main risk is not scratching but an impact to a prong, which loosens the setting without you noticing.

How often should the setting be checked?

Every two years, or immediately after a significant impact. This check is offered for life on our creations. A loose prong can be tightened in a few minutes; a lost stone can never be replaced identically.

My ring has lost its lustre, what should I do?

In most cases, it is not the stone but the metal: white gold is rhodium-plated, and this layer wears away within two to three years. Rhodium plating restores its whiteness. If the stone itself appears dull after cleaning, look beneath the setting — that is where the film of soap and dust settles.

Each family, its care

Sapphire rings Ruby rings Emerald rings Spinel rings Teal sapphire rings

Loose stones and their full characteristics can be explored from the page precious stones.

The collections