Certainly you can use silk! Did you ever see an old crazy quilt? They had everything you could imagine in them for "fancy" fabrics, cigarette silks, velvets, brocades, taffetas, neckties, satins, wedding laces, etc. etc. The silk won't wear in a quilt that gets a lot of use, but they are surely gorgeous to be used as wall quilts, or for decorating. Unless your silk is very thin you wouldn't need to stabilize it.