I'm sure it's milk glass. I picked this cameo up for $ix and change I 1st thought it was carved red carnelian, but now I'm not so sure? I think what I have is glass, but if it does turn out to be a carved stone, that will be better. I think your glass cameo would have a vintage jewelry value to collectors. If I had to guess I would say your cameo was made in the 1940s or 50s ??