This term in the gem trade usually applies to deeply colored or darker amethyst. Interactive guide to hundreds of rocks and minerals. It is purple on top and white or clear on the bottom
Amethyst Crystal Cluster Free Stock Photo - Public Domain Pictures
It may also be banded purple and white
Amethyst quartz is usually tumbled or polished into beads
May also be incorrectly used in the gem trade to describe any deeply colored amethyst. It has been ages since i was on here and i don't quite know how to pick up where i left off But i still have thunder bay amethyst and can send a flat rate usps mailer, medium, for $40.