​Hi everyone!

Is there someone out there who can help me date this button? It is
molded from op. black glass and 20 mm in diameter. It has a ground and
polished back. The edges have been ground as well to eliminate the mold
seam. There are two mold-imparted conical holes in the upper face that meet
a single conical hole in the bottom face. I think it is fairly early (16th
or 17th century?) but would like some concrete comparative information. If
a picture would help, contact me off line ([log in to unmask]).

Thanks!

Karlis