A Massive Modernist Sterling Silver and Amber Pin

This brooch was an online purchase a few years ago. The unusual casket-shaped piece of amber is probably hand faceted because it is slightly irregular. It is set in a thick solid silver frame. I did not find a signature and believe it could be a studio made piece. It's hard to determine its age, any time from 1970s to the recent present, late eighties - early nineties would be my best guess.