Antique Victorian Buttons

These buttons are a mystery to me. There are five of them. The buttons are heavy, weigh almost two ounces. Set with amethyst the metal is gold. I do not know if it is real gold or pinchbeck. Could be brass coated with gold. Magnet will not stick. They mesure 1 1/4" width.

They are so lovely. I have held on to them for several year hoping to find out something about the history surrounding these beauties. I would appreciate any information that someone out there might have that would enlighten me.