38	GEMS AND PRECIOUS STONES
	familar with, we owe to the industry and sharp sight of these children. It would aid much in the development of new min-eralogical fields if this plan of Mr. Stephenson's could be widely introduced. One of the minerals most likely to be mistaken for the diamond is a form of small quartz crystal found principally at Santa Fe and Gallup, N. M.; Fort Defiance, Ariz.; Deadwood, Dak.; and Shell Creek, Nev. These crystals range in size from i to 5 millimeters and the prism is nearly or entirely obliterated. In addition to this, as a rule, the surface is slightly roughened, and by an inexperienced person such a crystal is easily mistaken for an octahedron, which is almost universally considered to be the only diamond shape.