Here is a description of some materials used to manufacture prom dresses, formal gowns and homecoming dresses. The list is not complete, however it will give you a basic understanding of these materials.
Silk charmeuse is made with a satin weave, which is soft, yet, supple and drapes beautifully. The fabric is woven with a satin weave, where the warp threads cross over three or more of the backing threads. The front side of the fabric has a satin finish, lustrous and reflective, and the back has a dull finish. Silk charmeuse is most often used for loose-fitting, bridal gowns and slinky eveningwear. Charmeuse is somewhat difficult to sew because it is so slippery. Pins and needles leave marks, so pin only at the edges. It doesn't unravel much, however.
Chiffon for prom dresses, is elegant and sheer, with a slightly rough feel to it. Chiffon is lightweight, but strong. Chiffon is softer and thinner than Georgette, sometimes called 'Crepe Chiffon'.
Georgette is made like chiffon, but a two or three-ply yarn is used. Chiffon is most often used for loose, full, flowing garments and is popular for prom dresses, scarves and nightgowns. It is hard to cut out and sew because it is so flimsy and slippery. Also very important is the fact that it doesn't show pin holes.
Silk Organza is a sheer, thin open weave fabric that is heavier and crisper than silk gauze. It has a smooth, flat finish, is strong and durable, and gets its stiffness from tightly twisted yarns. Often used as the base fabric for embellished fabrics. Organza prom dresses are very lightweight and made of sheer material, but a bit stiff, and can be gathered for bouffant uses. Organza can be used alone or over other fabrics from tightly attire to loosely fitted blouses, dresses and evening wear. Also useful for facings, inter facings or lining. Silk organza can be used as an underlining to add crispness to parts of a garment. It sews easily, doesn't show pin holes and it holds creases well.