Plain weave silk. Tightly woven and very luxurious. If you are dealing with silk fabric before it is made into a garment, or if you are willing to take a chance with an existing garment, you can machine wash and dry it. It might shrink a little. Sizing is stiff, as is the gum that is on silk in its natural state.
Silk is a fiber made of protein, like wool or hair.
It was a symmetrical vinelike weave, with red and deep yellow and a metalic gold thread outline. Their brocades are quite nice, although they don't have the older style symmetrical brocades. They have a mail order business as well.