I remember reading somewhere, that rayon was used in the 30's and 40's but cotton and silk were more popular. I believe nylon was invented, but didn't actually become widely available 'til after WWII.
Is it possible for you to post a picture? Maybe someone will be able to identify era/possible fabric type. I agree with Mom-6, handquilting would be the best option. If it is fragile, there will be less scope for disaster.