UNITED STATES, CANADA AND MEXICO                            179
	like translucency, and become white and somewhat earthy in appearance, and exhibit the crypto-fibrous structure with more distinctness. Specimens cut and polished across the end of a slab-like mass show on one side a narrow selvage of breccia made up of fragments of the pectolite and of a dark-colored rock, mixed and firmly cemented together. On the opposite side or border of the mass, there are distinctly-formed parallel planes of concen­tric layering, from the surfaces of which the fibres diverge. These layers and the breccilated border opposite show the vein-like PECTOLITE
	formation of the mass between walls. Its hardness is from 6 to 6.5. It may be found useful as an ornamental stone for making small objects, cups, plates, handles, or for carving figures, or inlaid work." This is identical with the pectolite from Alaska, described by Prof. Frank W. Clarke. (See Jade, Chapter on Mexico.) Dioptase was first described by R. C. Hills as being found in the United States at the Bon Ton group of mines, about sev­enty miles from Clifton, Ariz., where it occurs in brilliant green