Epidote

The, Wolfscragg rock near Keswick has veins of Quartz accompanied by what is often called Prase, and which has a remarkably glaucous appearance; it seems to be Quartz intimately mixed and coloured by Chlorite. The Quartz is in some parts crystallized, and some of the spaces between the crystals are filled up with Chlorite; but more of them by Epidote in masses of stellated or fasciculated spiculæ, diverging from the sides of the vein, and of a yellowish green colour. The Quartz is white, and in some parts terminates in small dark ochraceous hollows; the ends of the crystals being stained with the ochre, as also happens with some of the ends of the Epidote crystals which now and then terminate in them, as in tab. 451. We have thus both the ingredients necessary for the formation of Prase, but without their being intimately mixed, while some of the Quartz has mixed with the Chlorite, and formed a substance nearly resembling Prase, but readily distinguishable by means of a glass or by the colour.