Article: Microminerals from Black Jack Canyon, Greenlee County, Arizona. (Contributed Papers in Specimen Mineralogy).

A new locality for western volcanic minerals (Henderson 1985) yields fine microcrystals of several species. The site is a wash that crosses Highway 78 between mileposts 162 and 163 near Black Jack Canyon, Greenlee County, Arizona. The specimens are found in the vesicles of rhyolite float. The source of the float is unknown, but the area to the east and north contains known Cenozoic-age rhyolites (Wilson and Moore 1958).

The minerals tentatively identified include quartz, with typical prism faces that are, however, rounded and show waviness in the rhombohedral terminations. Some crystals have inclusions of an unidentified black mineral. Ilmenite occurs as dull ...

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