How to Tell Real Silk From Fake: A Buyer's Guide
If you've ever paid £15 for something labelled "100% silk," there's a decent chance it wasn't silk. The word gets thrown around loosely in online listings, often stuck on polyester satin or viscose blends that share none of silk's actual properties. Telling the difference doesn't require a lab. A few simple checks, done properly, will tell you most of what you need to know.
The Burn Test: The One That Settles It
This is the most reliable method available outside a textile lab, and the reason it works comes down to basic chemistry. Silk is a natural protein fibre — biologically closer to hair or fingernails than to plastic. Polyester and most synthetic "silk" are petroleum-based, so they react to flame in an entirely different way.
Done properly: pull a few loose threads from an inside seam or hidden hem, never from anywhere visible. Hold them with tweezers over a fireproof surface, well away from anything flammable, and bring a small flame to the threads for a second or two.
Real silk won't catch and keep burning. It smoulders, self-extinguishes almost immediately, and gives off a smell close to burning hair — slightly acrid, distinctly organic rather than chemical. The ash crumbles into a fine grey powder between your fingers.
Synthetic fibres do the opposite. They melt instead of burning, release a sharp chemical smell, and the residue hardens into a dark bead that won't crumble — because what you're holding is essentially cooled plastic.
This test is destructive, so it only works on loose threads or swatches, not a finished piece you want to keep. It's also the test we rely on when sourcing fabric, since unlike touch or shine, a good weave can't fake the result.
The Touch Test: What Your Hands Already Know
Before burning anything, your hands will usually tell you something first. Genuine silk has a particular warmth — rub it between your fingers for a few seconds and it heats up slightly, the protein fibre responding to body heat. Synthetic fabric stays cool throughout, with a smoother, almost plastic slickness that doesn't shift no matter how long you rub it.
There's a sound difference too, sometimes called the silk rustle — a soft, crisp friction when two layers of real silk move against each other. Polyester tends to produce something flatter and squeakier. It's subtle, but once you've felt it on something you know is genuine, it's easy to recognise again.
This won't give you certainty on its own, but it's a useful first filter for deciding whether something is even worth testing further.
The Shine Test: Iridescent, Not Just Shiny
Silk fibres have a triangular cross-section, which means light refracts at multiple angles as the fabric moves. The shine shifts — sometimes warmer, sometimes cooler, depending on the angle and the light. It rarely looks uniformly bright from every direction.
Polyester satin is built to look glossy no matter how you turn it. The shine tends to be more even, often whiter or more metallic, and it doesn't shift the way real silk does. If a fabric looks identically shiny from every angle, that uniformity is itself a clue.
The Ring Test: An Old Trick That Still Holds Up
This one is more fun than precise, but silk traders have used it for generations. Take a plain ring and try pulling a length of the fabric through the centre.
Lighter-weight genuine silk glides through with almost no resistance. Polyester tends to catch, bunch, or drag. The test gets less reliable on heavier or densely woven silks, which may not pass through easily regardless of authenticity — so treat it as a supporting check rather than a final answer.
How This Plays Out in Practice
None of these need to happen in isolation. A sensible order: feel the fabric first, check how the shine behaves under light, then — if you want certainty and have a loose thread available — run the burn test.
This is roughly the process we use before any fabric goes into production. Every batch of Gambiered silk and mulberry silk we source gets checked this way, because labelling something "silk" without verifying it is exactly how counterfeit fabric ends up in finished garments. It's a small amount of friction in sourcing, but it's the difference between a label that means something and one that doesn't.
A Couple of Red Flags Worth Knowing
Price isn't proof, but it's a signal worth paying attention to. Genuine silk is labour-intensive — it takes roughly 5,000 silkworms to produce a single kilogram of raw silk — and that cost has to show up somewhere. A "100% silk" dress priced below a cotton equivalent is worth questioning before you buy.
Care labels tell their own story too. Most genuine silk needs hand washing or dry cleaning. A "silk" item marked machine washable on a normal cycle is more likely a polyester blend, since few finishes survive that kind of agitation intact.
Where That Leaves You
The burn test is as close to definitive proof as you'll get without sending fabric to a lab, and it's worth learning if you buy silk often. Touch and shine will get you most of the way for everyday shopping decisions, and the ring test is a decent party trick if nothing else.
Every fabric we use at The Silk Co — Gambiered silk and mulberry silk alike — goes through this same checking process before it reaches production. If you're shopping for something specific, our silk co-ord sets and cheongsam tops are made from verified mulberry or Gambiered silk.
