if you can bear to do this: snip a tiny piece of the cloth off. then, hold it over a candle flame (using tweezers). if the cloth melts, drips, or becomes plastic-y in any way, you have an artificial fiber on your hands. if it simply burns and then turns to ash, or even if it resists burning, chances are you have a natural fiber, possibly real silk.
you can google: "burn test for fabric" or other variations on that, and there are charts and sites which tell you how to identify a material by burning it and then observing its consistency, color, and even smell.

hope that helps.