How to tell real silk: five tests that expose a fake

The parcel arrives on a Friday. Inside, a slip in ivory, folded in tissue, with a label promising silk. Yet the moment it leaves the box and runs across the hand, something refuses to add up. The cloth stays cool. It slides too smoothly, too evenly, as though it wanted nothing to do with the body underneath.

Silk does not behave that way. Recognising it needs no laboratory and no microscope, only a few seconds of attention and five tests performed the same way for centuries: by hand, by eye, by ear and, as a last resort, by flame. Each answers a different question, and together they leave no room for doubt.

First test: touch and temperature

The simplest and the most reliable. Silk is a protein, the same one that builds hair, and it treats the body as something related to itself. It takes the warmth of a palm almost at once, in two or three seconds, and gives it back. Moments later it clings lightly to the hand as if it were an extension of it.

Polyester stays cool. It warms slowly and unevenly, leaving a hot spot exactly where the hand rested while the rest remains cold. Its smoothness is different too: slippery, uniform, without the faintest resistance. Real silk carries a barely perceptible grain under the fingertip, like very fine sand.

Test several places on the same garment. The lining, the inside of a facing, the strip beside a seam — if one part behaves unlike the rest, the cloth is a blend, or the pieces were cut from two different fabrics altogether. This happens more often than any label would suggest.

Second test: a lustre that shifts colour

A silk filament is an irregular triangle in cross-section and refracts light like a prism. Its lustre is therefore pearl-like and restless: turn the cloth and the colour moves half a tone, warmer, then cooler, while the highlight travels along the fold instead of sitting in one place.

Polyester satin shines differently — glassy, uniform, like film. The glare is white, hard, and holds the same shade at every angle to the window. Always judge this in daylight, never under a bulb: artificial light flattens the difference and can lend credibility to the cheapest cloth in the room.

The reverse side helps too. Genuine charmeuse has a lustrous face and a matte back, yet both read as the same fabric simply turned over. In cheap satin the reverse is often visibly other — grey, flat, technical, as if it belonged to a different garment.

Third test: the scroop and the way it recovers

Crushed in the fist, silk makes a sound the trade calls scroop: a quiet, dry rustle, closer to a footstep on snow than to paper. It is faint, and you have to look for it in a silent room, but once heard it can never be confused with anything else.

Polyester either says nothing or rustles plastically, higher and louder. The recovery differs as well. Released from the hand, silk straightens softly and slowly, keeping for a moment the faint memory of the creases before they resolve themselves. Synthetic satin springs back at once, elastic, as though nothing had happened.

That single second of delay matters more than it appears. It is precisely what governs the way a silk slip settles on the body — a fraction behind the movement, always half a breath after the figure. Synthetics cannot do this, which is why they look stiffer even when they are thinner.

Real silk returns to its shape a second later than the counterfeit. That second is the whole difference.

Fourth test: flame on a loose thread

This is the decisive test, and the only one that leaves no doubt at all. It also demands care. Perform it strictly on a loose thread drawn from a seam or an unseen edge, never on the fabric itself, held over a sink or a plate, well away from curtains and hair. One thread is entirely enough.

Silk burns like hair, because chemically it is nearly the same thing. It sputters briefly, goes out by itself once the flame is withdrawn, smells of scorched horn or feather, and leaves a black, brittle bead that crumbles to powder between the fingers. The smell is unpleasant and instantly recognisable.

Polyester behaves like the plastic it is. It melts rather than burns, shrinks away from the flame, draws into a thin filament and smells chemical, faintly sweet. What remains after cooling is a hard, shiny bead that will not crush at all. Viscose burns differently again — fast, with the scent of burning paper, leaving a pale, powdery ash.

Fifth test: label, weight and price

A true composition is written without ambiguity: one hundred per cent silk, soie, Seide, seta. Phrases such as silky satin, silk-touch or satin de soie describe an impression rather than a fibre — and they are perfectly legal, because they claim nothing about content. This is where a buyer most often finishes the sentence on the seller's behalf.

A serious description also states the weight in momme and the weave: charmeuse, crêpe, habotai. A house that knows its cloth quotes the number; a seller reselling finished pieces from a wholesaler usually does not know it. A missing figure proves nothing on its own, but its presence means someone has spoken to a mill.

Which leaves price — the least charming and the most honest indicator of all. A metre of silk needs thousands of cocoons, hand reeling and a slow loom. Below a certain threshold that arithmetic simply does not close, and no logistical brilliance changes it. A price that seems inexplicable is usually explained all too well: it describes the raw material, not good fortune.

What else the label says

Care instructions reveal more than the composition line. Silk asks for cool water, a mild detergent and drying flat, so the label speaks of 30°C, hand washing and no tumble dryer. A symbol permitting a 60°C wash or machine drying beside a claim of pure silk is a contradiction in itself.

Read the small print about the trimmings as well. Lace is often nylon even in a silk slip, straps are often elastane and linings viscose — and none of that is wrong, so long as it is written plainly. Silence about the component parts is rarely an accident.

The finishing gives things away too. Narrow hand-rolled scarf edges, French seams, lined straps and bound buttonholes cost hours nobody spends on a worthless cloth. How a piece is sewn is often a better clue to the fibre than the composition line itself.

What these tests will not settle

All five answer the question of whether silk is present, not how much of it there is. A blend of ninety per cent silk with a little elastane passes every one of them, because it behaves almost identically, only springier. That is an honest material, provided the label says so — the trouble is the silence, not the addition.

Viscose blends are the harder case. Viscose comes from cellulose, so it can feel cooler, look more matte, and recover slowly after crushing, much as silk does. Only the thread over a flame decides it: the scent of burning paper instead of burning horn. In a blended cloth you will smell both at once, and that is an answer too.

Wild silk, tussah, is a separate matter. It is coarser, warmer in tone, visibly slubbed and far less lustrous than mulberry silk, so it is often mistaken for a counterfeit while being silk in the fullest sense. Here the label and the burn test tell the truth, and the eye is the thing that lies.

Polyester satin sold under a silkier name now fills product descriptions in a way it did not ten years ago. The photographs are indistinguishable, the wording is carefully chosen, and the parcel arrives faster than anything could leave a workshop. Only the hand settles an argument the eye cannot.

Back to the slip from Friday's parcel: left over the back of a chair, it was still cool an hour later. Silk cannot manage that — it warms at the first touch and keeps that warmth long after it has been set down. At YES VERSE the cloth is chosen for exactly this patience with the body, because it is what remains once the label has faded.