![]() Several districts in western Nevada also have yielded abundant Apache tears eroding from tuff beds such areas have been popularized in the lapidary trade through guides for rockhounds. Where perlite is incompletely hydrated, fresh obsidian cores remain as pebbles of marekanite, or Apache tears this origin has been occasionally described in the geologic literature (for example, ).Īpache tears are well known from tertiary volcanic terrain in numerous localities throughout the western United States, particularly Arizona, from where specimens were widely collected and sold in the lapidary and specimen trade. Excessive water present during cooling and quenching of rhyolitic lava causes obsidian to hydrate (i.e., water entering the obsidian glass converts it to perlite). Formation is apparently related to differential cooling and various alkali and water contents. The spherules occur as cores within perlite masses that typically exhibit texture of concentrically curved, onion-skin fractures. Geology Īpache tears originate from siliceous lava flows, lava domes or ash-flow tuffs, often in close association with or embedded in, gray perlite. Apache tears fall between 5 and 5.5 in hardness on the Mohs scale. Internally the pebbles sometimes contain fine bands or microlites and though in reflected light they appear black and opaque, they may be translucent in transmitted light. ![]() Also known by the lithologic term marekanite, this variety of obsidian occurs as subrounded to subangular bodies up to about 2 in (51 mm) in diameter, often bearing indented surfaces. Apache tears are rounded pebbles of obsidian or "obsidianites" composed of black or dark-colored natural volcanic glass, usually of rhyolitic composition and bearing conchoidal fracture.
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