What Is It? The Amethyst BioMat is basically a narrow mattress filled with pockets of smooth amethyst stones. When you turn it on, it sends a gentle heating current through the stones, which causes a release of negative ions and far infrared rays that penetrate deeply into the body. The FDA supports many benefits of laying on this mattress including an increase circulation and relief from: Minor muscle pain Minor joint pain and stiffness Joint pain associated with arthritis M