Two baby blankets can look almost identical online — both “satin-trimmed,” both soft, both photographed on a pretty crib. Then they arrive, and one feels like a keepsake while the other feels like a poncho liner. The difference is almost always the trim. Here is what’s actually going on, and how to tell real silk from “satin.”
The quick answer
Silk is a fiber. Satin is a weave. That single distinction explains most of the confusion. Silk is a natural protein fiber spun by silkworms. Satin is just a way of weaving threads so one side comes out smooth and glossy — and those threads are usually polyester, acetate, or rayon, not silk at all. So “satin trim” almost always means plastic woven to look shiny. Real silk can be woven into a satin (that’s called charmeuse), but true silk charmeuse is far less common on baby products because it costs more.
What real silk charmeuse is
Charmeuse is a silk fabric with a luminous front and a soft matte back. Its weight is measured in momme (pronounced “mummy”) — higher momme means a denser, more substantial silk. A quality charmeuse for trim sits around 18–19 momme; anything much lighter feels flimsy. Because silk is a natural protein fiber, it is breathable and temperature-regulating: cool in summer, never clammy, and gentle against skin that reacts to synthetics.
What “satin” usually is
On most baby blankets, the shiny edge is polyester satin or an acetate/rayon blend. It photographs beautifully and costs a fraction of silk, which is exactly why it’s everywhere. But polyester traps heat, can feel slick or plasticky, and doesn’t develop the soft, lived-in hand that real silk does. It is not dangerous — it is simply not silk, even when the label leans on the word “satin” to suggest otherwise.
Why it matters for a baby
The trim is the part a baby touches most — the edge they rub between finger and thumb to settle themselves. A cool, breathable, natural-silk edge is genuinely soothing and holds up to years of that ritual. A synthetic edge is fine, but it’s the corner people replace, not the one they keep.
How to tell the difference
- Read the fiber, not the finish. Look for “100% silk” or “silk charmeuse,” not just “satin.” If a listing only says “satin” and never names the fiber, it is almost certainly synthetic.
- Look for a momme weight. Only genuine silk sellers cite momme. Its presence is a good sign.
- Feel for temperature. Real silk feels cool and then warms to your skin; polyester feels slick and holds a static, plasticky warmth.
- Mind the price. Real silk trim is more expensive to source and sew. A very cheap “satin” blanket is telling you what its edge is made of.
What we use, and why we say so plainly
Every Robbie Adrian blanket is trimmed in real 100% silk charmeuse at 18.5 momme, on a body of organic cotton, knit and hand-sewn in the USA. We name the fiber and the momme because we’d rather you know exactly what you’re buying than take “satin” on faith. If you’d like to see the full breakdown of our materials, our Materials & Standards page lays out every fiber and where it comes from.