Carbuncle (gemstone) Carbuncle (gemstone) A carbuncle is any red gemstone, most often a red garnet. The word occurs in four places in many English translations of the Bible. The English King James translation is a rendering of the Hebrew Masoretic text (Old Testament) and Greek Textus Receptus (New Testament). "Carbunculus" is a word used in Latin for a small coal (or charcoal), and also for any of a number of precious or semi-precious stones, especially those of a red color.; Jerome apparently chose the term because of its similarity in meaning to the Septuagint's ἄνθραξ ("anthrax" meaning "coal"), which was in turn
Garnet of the three minerals defines a pressure-temperature range in which the mineral could equilibrate with olivine plus pyroxene: the three are listed in order of increasing pressure for stability of the peridotite mineral assemblage. Hence, garnet peridotite must have been formed at great depth in the earth. Xenoliths of garnet peridotite have been carried up from depths of and greater by kimberlite, and garnets from such disaggegated xenoliths are used as a kimberlite indicator minerals in diamond prospecting. At depths of about and greater, a pyroxene component is dissolved in garnet, by the substitution of (Mg,Fe) plus Si for 2Al