Silk is a natural protein fiber produced by the larvae of a moth. It is the only natural filament fiber, a filament from a cocoon can measure 1000 meters!
In general, silk is considered a more durable fiber. It is a renewable resource, can be biodegradable and uses less water, chemicals and energy than many other fibers.
Wool is a natural animal fiber. Wool usually refers to fibers from sheep, although wool can also come from angora and cashmere goats, camels, alpacas, llamas, yaks, vicuña, possums, rabbits and more.
When it comes to sustainability, wool is a renewable resource that is biodegradable.