Porphyry was a philosopher whose now-lost works attacking Christianity were quoted by Saint Fidgeta's teacher, Putricordes (Saint Fidgeta and Other Parodies; 11). A wax tablet preserved in Santa Fidgeta originating from Fidgeta's school includes her name and the phrase "Jocus Porphyrias."
A rock consisting of crystals embedded in a compact dark red or purple groundmass. Like other semiprecious stones (cf. jade, jasper), it has been used as a person's name, including a Greek scholar and philosopher (c.232-c.304) who wrote extensively against Christianity. Suggests Charles Bowen: "John was calling on his personal encyclopedia of odd facts for this one."
Not to be confused with porphyria, a disease so named for bodily discolorations purple in color.