Noah Webster
Porphyry
POR'PHYRY, noun [Gr. purple; Latin 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.
Porphyry is very hard, and susceptible of a fine polish.
Porphyry is composed of paste in which are disseminated a multitude of little angular and granuliform parts, of a color different from the ground.