Organza, that crispest of crisp fabrics. Organza is a plain woven, very light weight fabric. There are no special twists in the yarn, although they are tightly twisted. What gives Organza the body we all love is the sericin, or silk gum.
When the bombyx mori start to spin their cocoons, they don't just tightly spin the fibroin around themselves. They also produce sericin, which is the gummy component that allows the fibroin to maintain it's cocoon shape until the bombyx mori crawls out of it's cocoon. Or until the cocoon is harvested for silk filaments. If you're a true blue Buddhist, you might want to skip cultivated silk. Lots of bugs die in the making of it. Don't worry, there is always Ahimsa Silk
Typically, once the cocoon is harvested, it is dropped in a vat of boiling water to remove the sericin as part of the processing to create the filaments for silk threads and yarns. But if the intended product is silk organza, most of the sericin is left on. This natural silk gum leaves the threads stiffer and is what creates the crisp, stiff, body of silk organza fabrics.
Organza is good for decorative embroidery work, as an over skirt, or to flat line a fabric that needs a little more body. Because of it's natural crispness, this is not a curve hugging fabric. Even on a bias cut, organza would be hard pressed to do anything other than fall in folds away from the body. It can be gathered, pleated, shirred, puffed, and bouffant-ed. It is genuinely versatile. Organza makes an excellent sew in stabilizer or facing fabric. You may have noticed I use Organza for ALL my stabilizing projects. However, given that it is a sheer fabric, seams need to be finished. Generally, I use french seams or flat-felled seams when finishing sheer seams. Or if I'm in a hurry and feeling lazy, I'll serge them. But french seams look the nicest, especially on fabrics where the seams are definitely visible.