porphyryPOR'PHYRY, n. [Gr. purple; L. porphyrites.] A mineral consisting of a homogeneous ground with crystals of some other mineral imbedded, giving to the mass a speckled complexion. One variety of Egyptian porphyry has a purple ground, whence the name of the species; but the homogeneous ground with imbedded crystals, being all that is essential to porphyry, its composition and colors are consequently various. |