Red Mercury

The science newsgroups have been a-buzz with tales of a 2-kiloton yield Russian red mercury fusion device, theoretically in the possession of terrorists. This, of course, prompts the question What Is Red Mercury? The answer to this question depends largely on whom you ask. Is red mercury real? Absolutely, but definitions vary. If you had asked me before I did a bit of Internet research, I would have given you the standard cinnabar/vermillion answer. However, the Russian tritium fusion is more interesting...
Cinnabar/Vermillion
Cinnabar is naturally-occurring mercuric sulfide (HgS), while vermillion is the name given to the red pigment derived from either natural or manufactured cinnabar.