Quick Answer
Three quick checks catch most fake silk: the burn test (real silk singes and smells like burnt hair, self-extinguishes, and leaves a crushable ash; synthetic melts, smells like plastic, and forms a hard bead), the feel test (real silk feels slightly warm and grippy, not slick and cool like polyester satin), and the price test (genuine mulberry silk rarely sells for bargain-bin prices given the labor-intensive production process). No single test is fully conclusive on its own, but two matching results are a strong signal.
The Burn Test
Snip a tiny thread from a hidden seam and hold it to a flame briefly. Real silk singes slowly, self-extinguishes once removed from the flame, smells like burning hair, and leaves behind a light, crushable ash. Synthetic fabrics like polyester melt rather than burn, continue burning after the flame is removed, smell like burning plastic, and form a hard, sticky bead instead of ash.
The Feel and Sound Test
Real silk has a subtle grip and slight warmth against skin, plus a soft, low-pitched rustle when rubbed between your fingers. Polyester satin tends to feel slicker, cooler, and produces a sharper, higher-pitched sound when rubbed — sometimes described as a faint squeak that real silk doesn't have.
Price as a Signal
Mulberry silk requires labor-intensive harvesting from silkworm cocoons, which keeps production costs meaningfully higher than synthetic alternatives. A pillowcase priced dramatically below typical market rates for "100% mulberry silk" is a signal worth investigating further, even if it isn't proof on its own.
Reading the Label
Check for momme weight (a genuine silk product usually lists this, typically 19-25mm for pillowcases) and fiber content. Listings that only say "satin" without specifying silk fiber content are describing the weave, not the material — satin can be made from polyester, and that's a completely different product than mulberry silk despite the similar sheen.
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FAQ
What does real silk smell like when burned?
Burning silk smells like burnt hair, since both are protein fibers, and produces a light ash that crushes easily between fingers.
Can I tell real silk from satin just by looking at it?
Not reliably — polyester satin can closely mimic silk's sheen visually. Feel, sound, and the burn test are more accurate than sight alone.
Does momme weight guarantee a product is real silk?
No, but a genuine silk listing will almost always state momme weight since it's a standard silk industry measurement; its absence is a minor red flag worth asking about.