I've read that gravity is supposedly the expression of a force carrier particle, the graviton, just as electromagnetism is a phenomenon produced by electromagnetic particles like light or radio waves. Example:
Lisa, I doubt if it's glass, but resin is a very likely material. Resins can vary in weight depending on the chemical they are made from. If it was made from stone you would see some indication of the nature of the stone. Though resin can be made to look like stone. Find the manufacturer of the piece and email them, it's likely they would be pleased to hear from you and tell you what the cameo is made from.
Yes and Steven Spielberg knows where you go swimming.