Silk comes in all types of thicknesses and textures, the ones I most commonly use are:
Habotai or Chinese Silk: it is semi- transparent, with a lovely sheen and nice silky touch.
Chiffon Silk: gauzy and transparent, with a more textured feel.
Charmeuse Silk: thick, rich and with a fanstic glossy silken sheen. The most exclusive silk I use.