Sweater Materials: Merino, Cashmere and Acrylic
Merino is fine sheep's wool, cashmere is a goat's soft undercoat with a legal fineness limit, and acrylic is a synthetic that costs less but pills sooner.
By Adolph GreenContributing writer.
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The short answer
- Merino is wool from Merino sheep. Its fibers are much finer than ordinary wool, so it feels soft against the skin and suits sweaters you wear all day.
- Cashmere is the fine, dehaired undercoat of the cashmere goat. Each goat gives very little of it, which is why it costs more.
- Acrylic is a synthetic fiber made to imitate wool. It is light, warm and cheap, but it pills sooner and breathes less than the natural fibers.
Merino vs cashmere
Fineness is measured in microns (one millionth of a meter). Lower numbers mean finer, softer fiber.
| Merino | Cashmere | |
|---|---|---|
| Animal | Merino sheep | Cashmere goat (undercoat only) |
| Typical fineness | Generally under 22 microns | No more than 19 microns on average, by US rule |
| Yield per animal | About 4.5 kg of fleece per sheep | About 0.2 to 0.3 kg of down fiber per goat |
The Woolmark Company gives the merino and yield figures, and notes that a human hair is 50 to 100 microns. The yield gap explains most of the price gap: one goat gives a small fraction of what one sheep gives.
Softness overlaps more than the names suggest: Woolmark says merino can even be softer than cashmere. Fineness varies from garment to garment, so check the label, and the micron figure if the maker gives one.
What the cashmere label has to mean
In the US, the Federal Trade Commission's wool rules (16 CFR 300.19) set the bar for the word "cashmere" on a label:
- the fiber must be the fine, dehaired undercoat of the cashmere goat;
- its average diameter must be no more than 19 microns, with a coefficient of variation of no more than 24 percent;
- no more than 3 percent of the fibers, by weight, may average over 30 microns.
So a cashmere label is a fineness promise, not just a name.
Where acrylic fits
The FTC's textile rules (16 CFR 303.7) define acrylic as a synthetic polymer with at least 85 percent acrylonitrile by weight. The trade publication Fibre2Fashion describes it as lightweight, soft, warm and affordable, which is why it shows up in sweaters, hats and socks, often blended with wool or cotton to bring the price down.
The tradeoffs it lists:
- Moisture: acrylic takes up only 1 to 3 percent moisture, so it dries fast but feels less breathable than natural fibers.
- Pilling: pilling resistance is moderate to low, so small fuzz balls form with wear.
- Heat: it is thermoplastic, with a melting range of about 160 to 250°C, so keep it away from a hot iron.
Woolmark, for its part, describes merino as breathable and able to absorb moisture vapor and odor before you notice it.
Which to pick
- All day, next to skin: fine merino.
- Softest feel, special occasion: cashmere, with care.
- Low price, easy care: acrylic or a blend, accepting some pilling.
How we count
The chart shows the style each sweater listing on Wiki Shopping states; 128 of the 419 sweaters listed on October 26, 2026 state one. Materials are read from product names: 32 names mention cotton, 11 wool and 2 cashmere, while none name merino or acrylic, so check each listing's fabric details. Browse the full range from clothing, shoes and jewelry. Counts change as listings are added or removed.