How to clean jade, and what actually harms it

Two figures explain almost every rule that follows. GIA puts jadeite at 6.5 to 7 on the Mohs hardness scale and nephrite at 6 to 6.5, and describes both as having exceptional toughness, very resistant to breaking or chipping. Hardness and toughness are different properties, as the types page explains, and a piece of jade is unusual in being middling at the first and extraordinary at the second.

Middling hardness means it scratches. Quartz sits at 7, which is level with the hardest jadeite and above every nephrite, and ordinary household dust is full of quartz. A bangle worn daily for thirty years has been very gently sanded for thirty years, which is one reason old jade has a soft rather than a glassy surface, and one reason you do not scrub it with anything abrasive. Sapphire, diamond and the mineral glass on a watch face will all cut it outright.

Extraordinary toughness means that the things that shatter most stones do not shatter jade. It survives being dropped on carpet, knocked on a table, worn through decades of doors and car handles. What it does not survive is a sharp blow on something harder than itself at an angle it cannot flex around, which is why every broken bangle story on earth involves a tile floor, a bathroom sink or a granite counter, and never a puddle.

The method is short because the stone is not the problem; the film on it is. Skin oil, soap scum, sunscreen and hairspray build a haze that reads as dullness, and people respond to dullness by reaching for a product. Do not. A bowl of warm water, a drop of the dish soap you already own, and a soft toothbrush worked into the carving and along the inside of the ring where the wrist has been. Rinse in clean water until it squeaks, dry with a cloth that does not shed, and hold it up to the window. That is the luster the cutter gave it, back.

GIA adds one line worth quoting, because it decides everything else on this page. Ultrasonic and steam cleaners are safe for untreated jade, but because jade is so often dyed or bleached, warm, soapy water is always a safe choice. The reason is that the jeweler's machines are hard on the two things a treated stone is hiding: an ultrasonic bath can work a filled fracture open, and steam heats the resin inside it. If you do not hold a certificate that says the piece is untreated, assume it might not be and use the bowl.

Two things never to use. The first is anything acidic or caustic: GIA notes plainly that jade can be affected by warm acids, and the descaler, the bleach and the oven cleaner all qualify. The second is a hot needle, which some forum will tell you reveals treatment by making the surface sweat. It does, sometimes, and Fritsch and his co-authors, who tested it in 1992, recommend against it because it damages the stone and because, as the next section explains, the sweating proves less than people think.

Nearly every jade shop will tell you to nourish the stone, and a good many will sell you the oil to do it with. The Chinese verb is yang, the same word you would use for raising a child or keeping a plant alive, and it carries the picture of a stone that is faintly alive and needs feeding. It is a lovely idea, and it is a folk version of something the trade genuinely does, just not with oil and not by you.

The 1992 paper that first documented polymer-treated jadeite begins its survey of treatments with a plainer one. For at least thirty years, the authors write, most jadeite jade has been coated with a thin film of paraffin or wax to improve its luster and fill fractures and pits, and material that has received only this superficial waxing is what the trade calls A jade. Later in the study they are blunter: although every untreated sample had been presented to them as untreated, virtually all such material, rough as well as polished, is waxed before it enters the market. Four of their twenty-seven untreated stones sweated under the hot needle, and the infrared spectrum showed why: residual wax from polishing, a common final step in much of Asia.

So the bangle on your wrist already has the coating the trade considers correct, applied by people who do it for a living, and the reason it looks better after a decade on you is not that you fed it. It is that skin oil has worked into the microscopic fissures at the surface and reduced the scattering of light there, and that cloth and skin have buffed it more evenly than any wheel. The meaning page takes that saying apart properly. Here the practical conclusion is enough: oil from a bottle adds nothing the wax does not, holds dust, and on a treated piece can find its way into whatever the resin left open. Wear it. That is the nourishing.

Chinese collectors do have a vocabulary for this, and it is worth knowing because it shows the tradition understood the mechanism all along. They distinguish handling a stone slowly, against the body over years, from working it hard in a cloth day and night, and a third way that is really about the owner's attention rather than the stone. The slow way is the one the bangle on your wrist is quietly doing.

The everyday questions come down to eight situations, and the honest answer to most of them depends on one thing you may not know: whether the piece has been treated. The real or fake page explains the A, B and C classes and why only a laboratory can settle which one you own. The table gives both answers.

The heat row deserves its footnote. The 1992 authors, having documented the resin, add that any polymer or polymer-treated product is likely to be damaged by exposure to high heat, such as that produced by a jeweler's torch, and that the cautions for other resin-treated stones apply. A torch is hundreds of degrees; a sauna is not. Nobody has published where between the two the resin begins to suffer, so the honest rule for a treated piece is to stay well below the question. For untreated jade the same paper is reassuring by omission: heat is listed as a treatment hazard, not a jade hazard, and GIA's only heat warning is the torch.

The durability row is the one people do not expect. The paper reports that bleached jadeite, before the resin goes in, can be so brittle that the lowest grades crush under finger pressure, and that treated pieces have been known to exude yellow residues after six months to a few years and to go darker and grayer in normal wear. The resin is holding a hollowed stone together. It does that well for a while, and it does it less well every year, which is the practical reason the price page says treatment is a switch rather than a dial.

A chip is a cosmetic problem with an honest fix. A jade cutter can polish it out, which removes a little stone and can leave a faintly thinner spot on a bangle, and the piece is otherwise the piece it was. Ask first how much material will go, since a bangle's value sits in its being one uninterrupted ring.

A crack is different, and this is the one place on the page to be firm. A cracked bangle is a ring waiting to fail, and a ring that fails on a wrist fails against skin. Stop wearing it. The traditional repair is to bind the cracked section in a sleeve of gold or silver, which is structural, visible and honest about being a repair; the modern one is to have the ring cut into pendants or beads that carry the same stone forward in a shape that no longer bears load. The meaning page covers what people say a broken bangle means. What a cracked one means is that it should come off, and the bangle size page explains how, including when to let a clinic do it.

A hairline you cannot feel with a fingernail may be a natural fissure rather than a crack, and jade is full of those. The test is a strong light through the stone: a fissure is inside the material and stops; a crack reaches the surface and continues. When in doubt, a jade cutter will tell you in a minute what a forum will argue about for a week.

On its own, in cloth. Jade scratches anything softer than itself and is scratched by anything harder, and a jewelry box is a bag of both. A bangle in a drawer with a diamond ring will lose; a bangle in a drawer with a pearl necklace will win, and neither result is one you want. The soft pouch it came in is the right container. Sunlight does nothing to natural jade, and GIA lists it as stable to light. Dry air does nothing either. The century-old piece in a family drawer is unchanged for the simple reason that nothing in a drawer can reach it.