text: what is carbuncle ?   carbuncle   as a medical term a ]] larger than a boil, usually with one or more openings draining pus onto the skin. it is usually caused by bacterial infection.   in gemology a carbuncle is a term for a convex, unfaceted, deep-red garnet.   in the bible the word carbuncle occurs in three places in most translations of the bible. each use originates from the same hebrew word בָּרְקַת בָּרְקַת or bâreqath bâreqath (baw-reh'-keth, baw-rek-ath'). in this sense, a carbuncle is usually taken to mean a gem, particularly a deep-red garnet, unfaceted and convex; however, the hebrew definition is less definite and the precise color of the gems is not known.