Precious Gem stones production in 1908 Page 45



	822	MINERAL RESOURCES.

	Springs and extending southeasterly from the east side of Cameron Cove along the slopes of the mountains for a distance of 3 miles. Numerous prospect holes in the Crystal Park region with the less valuable crystals left on the dumps show the past activities of mineral collectors. Fine quartz crystals occur at numerous places outside of the Crystal Park region and especially to the northwest, toward Pikes Peak, more amazon stone has been found. The rock of this region is principally coarse biotite granite composed chiefly of light flesh-colored potash feldspars, a white plagio-clase feldspar, gray quartz, and biotite mica. Pegmatite occurs in dikes, veins, and irregular masses through the granite. The crystals of amazon stone occur in the cavities or pockets in the pegmatite. The pockets vary from less than 1 inch to nearly 2 feet across. Some of these pockets are miarolitic cavities in the granite, around which the crystallization is coarse and the same as in pegmatite. In some cases the miarolitic pockets are connected by seams or veinlets, and can be readily traced for yards. In other cases the pockets are isolated, and others may or may not be found near by. The pockets are lined with crystals of amazon stone, smoky and clear quartz; occasionally topaz and phenacite are present. The crystals of amazon stone are generally well developed, and vary in size from a fraction of an inch to 3 or 4 inches square. The color ranges from gray to bright green and is often richer in one portion of a crystal than in another. The crystals from the shallow prospects are often more or less stained with iron rust both on their surfaces and along cleavage cracks. The rust may be removed with oxalic acid to prepare the crystals for mineral collections and for sale as gem material. Quartz crystals are found ranging from a fraction of an inch to several inches across, either singly or in clusters of parallel grown crystals. Some are colorless, though the majority are more or less clear smoke colored, sometimes very strongly so. They furnish fine cabinet specimens for mineral collections. Whitman Cross ^a and W. F. Hil-lebrand describe the occurrence of the specimen minerals of this region. Those observed were microcline, albite, biotite, quartz (smoky and clear), fluorite, columbite, gothite, hematite, and limonite, arfvedsonite, astrophyllite, and zircon. As much as a ton of crystals have been found in one pocket. Amazon stone and crystals of the associated specimen and gem materials, quartz, topaz, and phenacite, were mined by J. D. Endicott during 1908 in the Crystal Peak region 4 miles north of Florissant, Teller County. The occurrence of these minerals at this locality is evidently similar to that of the Pikes Peak region. The country rock in each case is coarse granite. Mr. Endicott states that the crystals are found in leads of pegmatite, which can be traced from a few feet in some cases to over a hundred yards in others. In the deposits opened the pegmatite is nearly in blanket form. The amazon stone occurs in streaks and pockets in the interior of the "veins" and attains a thickness of 1 foot in places; in other places it is absent. Troughlike depressions occur in places in the cavities, and in these the amazon stone is stained and coated with films of oxide of iron. Evidently the troughs served as channels for a later deposition of limonite from solutions. Some of the amazon stone is of good gem quality and has a rich green and blue-green color. Other stones are pale or badly Minerals from Pikes Peak : Am. Jour. Sci., 3d ser., vol. 24, 1882, pp. 281-286.