carbuncle

noun

1. (archaic)A deep-red or fiery colored garnet or other dark red precious stone, especially when cut cabochon.

   “With eyes like carbuncles, the hellish Pyrrhus […]”

   “And I will make thy windows of agates, and thy gates of carbuncles, and all thy borders of pleasant stones.”

   “His turban, or mandil [mandīl], was of finest white silk interwoven with gold, bestudded with pearl[s] and carbuncles; […]”

   “A piece of marigold or bay leaf was imbedded in the metal, and over it a carbuncle or chrysolite was placed.”

2. A charge or bearing supposed to represent the precious stone, with eight sceptres or staves radiating from a common centre; an escarbuncle.
3. An abscess larger than a boil, usually with one or more openings draining pus onto the skin. It is usually caused by staphylococcal infection.
4. An unpopular or ugly building; an eyesore.