Illusional wrote an excellent review on this specific corset which you can view here: link She even includes photos! She even gives a list of information about the material you're wondering about. Here is a section of her review. I've copied and pasted it for you.

"This corset is made out of acetate. Acetate is a wonderful fabric and is known for:

* Luxurious feel and appearance
* Wide range of colors and lusters
* Excellent drapability and softness
* Relatively fast drying
* Shrink, moth and mildew resistant

Acetate usually requires dry cleaning, so take care of your lovely corset!" less