Hi there dress

Hi Emma, thanks for your question! Unfortunately, there’s no second tag on the dress, so I can’t say for sure what the fabric is. I’m not an expert, but it has a silky feel to it—though it's a bit rougher than pure silk. It’s definitely not your everyday type of fabric.

Hi there, the waist is actually stretchy. I'm usually a size 10, and it fits me comfortably with extra room. I've attached two more images for reference, but I can't guarantee it would fit a size 12.