Wool versus Cashmere Comforters? Wool would be the warmest. Cashmere is a lighter fiber. One of the differences is that our wool is Pure Grow Wool. What this means is that the sheep are raised in humane standards in fields that do not have pesticides. And it is created without bleaches, formaldehydes, dyes, or animal cruelty. It comes from the only known company in the US that does not carbonize the wool. Usually, animal fibers are carbonized. After shearing the animal, they process the wool with acid. It is this acid that some people have allergic reactions to. This is usually why people say they are allergic to wool. They are not usually allergic to the wool itself; they are usually allergic to the carbonization.