Board Thread:General Discussion/@comment-4224349-20150108233407/@comment-233389-20150113185419

The bit about "precious" gems is amusing because Ruby and Sapphire are the same mineral. :p Ruby is the red form of Corundum, and Sapphire is.... any other colorful variety. (Sapphire is usually thought of as blue, but the term covers green, yellow, orange, purple, and pink too)

Garnet is not a specific mineral though so I guess discussing chemistry is pointless here. Amusingly, one form of Garnet is MORE valuable than most emeralds.