TALC n. A species of magnesian earth, consisting of broad flat smooth lamins or plates, unctuous to the touch, of a shining luster, translucent, and often transparent. By the action of fire, the lamins open a little, the fragment swells, and the extremities are with difficulty fused into a white enamel. When rubbed with resin, talck acquires positive electricity. Its prevailing colors are white, apple-green and yellow.

Of this mineral, Jameson's sixth subspecies of rhomboidal mica, there are two kinds, common and indurated.