Precious Gem stones production in 1914 Page 61



	310 MINERAL RESOURCES, 1914----PART II.

	associated with a great many worthless pebbles, such as black and red jasper, quartzite, white milky quartz or chalcedony, and waxy gray chalcedony. A quantity of the waxy chalcedony is found in place and loose on the surface between the Mcintosh ranch and Lankin Pass. The agates range from opaque white and gray to highly translucent gray with black, dark brown, reddish to yellowish-brown dendritic markings. Those with the black and dark-brown markings are most common. The dendrites consist of tufts or patches of oxides of manganese and iron. They show great variations in size and in delicacy of pattern. Some are small rounded tufts too dense to show individual lines, and others are as much as 2 or 3 millimeters across, exhibiting very delicate, mosslike or seaweed-like markings. The black dendrites furnish the prettiest gems. Groupings of the dendrites in such manner as to show complex landscapes, as in the Montana moss agate, apparently do not occur, and the gems depend on the perfection of the individual dendrites for. their beauty. The agate beds have not been exploited commercially to the present time. Most of the specimens have been collected by occasional visitors who have not placed the stones in the regular gem market. AMETHYST. PENNSYLVANIA. The occurrence of amethyst at many localities in Chester and Delaware counties, in southeastern Pennsylvania, have been mentioned by Kunz ^x and Dana.² The localities given include, in Chester County, several places in east Bradford, Pocopson, Birmingham, and Newlin townships; and in Delaware County, Aston, Birmingham, Chester, upper Chichester, Concord, Edgemont, Marple, Middletown, upper Providence, and lower Providence townships. Most of these discoveries were made before 1890, and since that time only occasional amethysts have been found. The majority of the amethysts have not been of fine quality, but a few specimens of fine crystals capable of yielding beautiful gems have been obtained. At present very few persons in the region take an interest in these minerals or know of the localities, and since much of the land has grown up in brush or been turned into meadow, there are few opportunities for the further discovery of amethyst. An examination was made of one of the old localities near Village Green, in Aston township, now owned by G. L. Mills. Some pits in a field on this place where good amethyst was obtained, are now filled up. A careful search on the ground near the pits yielded only a few colorless quartz crystals. No rock crops out around these amethyst pits, but the area is mapped as Wissahickon gneiss by F. Bascom.³ Mr. John H. Smedley, of Media, who was formerly much interested in the minerals of this region, knows the location of many of the amethyst deposits. He states that few finds of value are now made and that under the present conditions much prospecting and digging will be necessary to uncover gem material at many of the places. ¹ Kunz, G. F., Gems and precious stones, pp. 112-115, Scientific Publishing Co., New York, 1890. * Dana, J. D., System of mineralogy, 6th ed., pp. 1067-1088, 1909. a U. S. Geol. Survey Geol. Atlas, Philadelphia folio (No. 162), 1909.