Is cashmere a type of wool?

Loosely it is grouped with wool as an animal fiber, but strictly cashmere is not sheep's wool. It is the fine underdown of the cashmere goat, so it is a different fiber from a different animal, finer and warmer but less durable than sheep's wool.

Is cashmere warmer than wool?

Yes, gram for gram. Cashmere's very fine fibers trap more air, so it is warmer for its weight than ordinary wool. Wool is still very warm and is more durable and elastic, which is its own advantage.

Why does cashmere pill more than wool?

Cashmere fibers are shorter and less elastic, so loose ends migrate to the surface and tangle into pills more readily. Wool, especially springy fine wool like merino, recovers its shape better and resists pilling.

Side by side

Wool vs Cashmere

Wool and cashmere are both animal fibers, but one is a category and the other a luxury within it. Wool, in the everyday sense, is the fleece of the sheep, ranging from coarse to very fine. Cashmere is the soft underdown of the cashmere goat, far finer and warmer than ordinary sheep's wool but less elastic and less durable. The comparison is really fineness and warmth against resilience and value.

Wool

No. 127

the fleece fiber, woven or knitted · first documented Antiquity

Cashmere

No. 109

fine woven or knitted, from cashmere down · first documented Middle Ages

The differences

Aspect	Wool	Cashmere
Animal	The fleece of the sheep.	The combed underdown of the cashmere goat.
Fineness and softness	Ranges from coarse to fine; can be slightly prickly unless fine.	Extremely fine and soft, with a plush, smooth hand.
Warmth for the weight	Warm, and warmer than most fibers.	Warmer still; exceptional warmth for very little weight.
Durability and elasticity	Springy, resilient, holds shape, resists pilling well.	Less elastic; pills more easily and wears faster.
Cost	Affordable; a sheep yields a full fleece each year.	Expensive; a goat yields only a few ounces of down a year.

Which to choose

For everyday warmth, resilience, and value, ordinary wool wins, and fine merino narrows the softness gap considerably. For the softest, warmest, most luxurious hand, cashmere leads, at a much higher price and with more care required. Cashmere is, strictly, a kind of fine animal fiber that is not sheep's wool at all.

Common questions

Is cashmere a type of wool?: Loosely it is grouped with wool as an animal fiber, but strictly cashmere is not sheep's wool. It is the fine underdown of the cashmere goat, so it is a different fiber from a different animal, finer and warmer but less durable than sheep's wool.
Is cashmere warmer than wool?: Yes, gram for gram. Cashmere's very fine fibers trap more air, so it is warmer for its weight than ordinary wool. Wool is still very warm and is more durable and elastic, which is its own advantage.
Why does cashmere pill more than wool?: Cashmere fibers are shorter and less elastic, so loose ends migrate to the surface and tangle into pills more readily. Wool, especially springy fine wool like merino, recovers its shape better and resists pilling.

Full entry: Wool Full entry: Cashmere

Sources & References

1.Wool, Wikipedia
2.Woolen, Wikipedia
3.Cashmere wool, Wikipedia
4.Cashmere goat, Wikipedia