Just can't seem to figure this one out

Black amethyst vase with spade shaped leaves and veined. Approximately 8" in height. Vase appears to have a metallic coating, but when held up in the sunlight, glass has a distinct purple hue. Top part and base both have leaf like etchings in the bevels. Bottom reveals that the piece is hand blown. There are no markings to identify the piece.

Vase was obtained at an antique mall in Southeast Missouri. The more I examine it, the more details I find. It is a great conversation piece, and I cannot find anything similar in my own searches. Can anyone help identify this piece?