It's good to know the difference between wool vs. cashmere, and understand which one to pick and why.
1. Cashmere is eight times warmer than sheep's wool. It is also significantly lighter if the garment is made of high-quality, 100-percent cashmere.
2. All-wool is fabric of any description in which yarns are 100 percent wool from sheep. Other wools, such as angora, alpaca, camel, cashmere, mink and rabbit are named for the animal providing the fiber. They must be present in amounts of 25 percent or more to alter the properties of the blend.
3. Cashmere comes from the hair of goats, and alpaca from alpacas. Merino used to denote the wool of Merino sheep, but now is used in a wider sense. It's generally a very soft wool, though still not as soft as cashmere or alpaca.
4. Durability will depend heavily on the quality. In general, merino wool is the sturdiest, though the least soft, and is usually the cheapest. High-quality cashmere is durable but very expensive, and cheap cashmere tends to be very shoddy.
5. The difference between these fibers can be seen if we look at the following electron micrograph.
Immediately we see that coarse wool is much larger and rougher looking than the other fibers. The fine wool is much thinner and it's scales aren't as large, but if we compare it to cashmere, it becomes very obvious how the fine wool has a lot more scales.
These scales have a lot to do with why wool and low quality cashmere feels itchy. When the fiber runs against skin, these scales can 'catch' on the skin causing irritation. People with very sensitive skin will have a stronger reaction to this than others.
6. The softer the wool the more likely it is to pill, because the fibers are shorter.
7. The common factor of both these woolen items is that they are warm, stylish and very expensive. So, if you are investing in either, treat them well and use them rightly.