[Fr., from Gk.porphyrites : porphyra, purple.] A hard, finely-grained stone or rock, having a compact felspathic base, through which are scattered distinct crystals of one or more minerals. Porphyry may be green, with blotches of paler green or white; or red, with white blotches or specks ; and has other shades of color. The blotches of a polished surface are the felspar crystals. The rock abounds in Egypt, in the northern part sof Europe, i n South America, and in Mexico. All the varieties are esteemed as marbles, and used in fine sculpture-work.