How to tell if vintage silk is real silk

Hi, hello. Here's how I check whether a vintage blouse is actually silk or just dressed like it. Some of this you can do standing in the thrift store aisle, and one test (the burn test) is for when you get it home. No single clue is proof, so the real trick is stacking them up.

Why is it so hard to tell silk from synthetics?

Because the fakes were made to fool you. Rayon and acetate were literally sold as "artificial silk" back in the day, and modern polyester and nylon can be made to copy silk's drape and shine. It doesn't help that the words we use for silky fabrics aren't fibers at all.

Is satin silk?

Not necessarily. Satin is a weave, not a fiber, so a satin blouse can be silk, polyester, acetate, rayon or nylon. Same goes for other names you'll see on tags and listings:

• Satin: a weave with long floating threads that make one side shiny.
• Charmeuse: a lightweight, drapey satin. Silk charmeuse exists, and so does a lot of polyester charmeuse.
• Chiffon: a sheer, floaty fabric. Silk, polyester and nylon chiffon are all out there.
• Crepe de chine: a light crepe with a soft, slightly pebbly feel. Originally silk, often polyester now.

What can I check at the thrift store?

Start with the label, then use feel and sheen as hints. None of these are proof on their own, but together they'll tell you whether it's worth buying to test at home.

• No content tag doesn't mean fake. US fiber content labels were required starting in 1960. Lots of earlier pieces never had one, and tags get cut out all the time.
• "Artificial silk" or "art silk" means not silk. That was the old name for rayon and acetate.
• Brand names count. Celanese is a trademark for acetate. Dacron is a brand of polyester.
• Check which part the tag is talking about. Sometimes only the lining or trim is silk, or the shell is silk and the lining is acetate.
• Feel: silk tends to feel soft and warms up fast in your hand, while a lot of polyester feels slick and stays cool. Good polyester is convincing, though, so it's a reason to look closer, not a verdict.
• Shine: silk usually has a soft, shifting shimmer rather than a flat shine. Acetate is known for getting close, so it's a hint, not proof.
• Era clues: nylon showed up in 1939 and polyester in 1953, so a piece that's truly from the 1930s isn't either one. Rayon and acetate were around earlier, though.

How do I do a burn test safely?

Take a tiny snip from a hidden spot, hold it with tweezers over a sink or foil, and touch a flame to it. Only do this on something you own, at home.

1. Snip from a seam allowance or hem. A few threads is plenty. Test threads running both directions if you can, since they can be different fibers.
2. Use tweezers, not fingers. Some fibers melt and drip, and melted synthetic sticks to skin.
3. Work over a sink or foil, with water nearby and your hair back.
4. Bring the flame in slowly, then pull it away and see if it keeps burning.
5. Smell it and check what's left once it's cool. Try crushing it between your fingers.

What does each fiber do?

• Silk burns slowly, tends to go out on its own, smells like burning hair, and leaves a dark, brittle bead that crushes into gritty powder.
• Polyester and nylon melt, can drip, smell chemical, and leave a hard bead you can't crush.
• Rayon burns fast like paper, smells like paper, and leaves soft, feathery gray ash.
• Acetate burns and melts, smells a little like vinegar, and leaves a hard bead. It can look like silk's bead, but it won't crush.
• Weighted silk (treated with metal salts in the late 1800s and early 1900s) chars and holds its shape. It's also the stuff that shreds as it ages, so handle it gently.
• A little of both (some ash, some melting) probably means a blend.

Why should I combine tests?

Because every test has a way to fool you. What I go by is agreement: if the tag says silk, it feels and moves like silk, and the snip burns slow, smells like hair and crumbles, you've got silk. If the clues fight each other, treat it as unknown and price it that way.

Which "tests" should I skip?

• The pin test. How easily a pin goes through depends on the weave, not the fiber.
• The water drop test. Finishes and weave change how fast water soaks in, and water can spot silk.
• The weight test. Silk comes in everything from sheer chiffon to heavy satin.
• Price. At a thrift store, whoever tagged it set the price, not the fiber.
• Silk Mark. That's a label for new silk products. You won't find it on a vintage blouse.

FAQ

Can I tell real silk just by touching it?

Not reliably. Good polyester and old rayon and acetate can feel close to silk. Use the label and a burn test to back it up.

Is the burn test going to ruin my blouse?

Not if you take a tiny snip from a seam allowance or the inside of a hem. Never hold a flame to the garment itself.

My vintage blouse has no fiber tag. Is it fake?

No. US fiber labels weren't required until 1960, and tags get cut off.

Is satin real silk?

Satin is a weave, not a fiber. It can be silk, but it's just as often polyester, acetate or rayon.

If you'd rather skip the detective work, I've got vintage pieces in the shop. Look through vintage dresses and gowns or everything in true vintage. For more fabric and dating questions, see the vintage FAQ.