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Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is a glass made from the fused volcanic rock dust from Mount St. Helens and marketed as a gemstone. [ 1 ] [ 2 ] Helenite was first created accidentally after the eruption of Mount St. Helens in 1980 .
Obsidian scalpels older than 2100 BC have been found in a Bronze Age settlement in Turkey. [48] In the eastern Mediterranean area the material was used to make tools, mirrors and decorative objects. [49] The use of obsidian tools was present in Japan near areas of volcanic activity. [50] [51] Obsidian was mined during the Jōmon period.
The Vishnu Basement Rocks is the name recommended for all Early Proterozoic crystalline rocks (metamorphic and igneous) exposed in the Grand Canyon region. They form the crystalline basement rocks that underlie the Bass Limestone of the Unkar Group of the Grand Canyon Supergroup and the Tapeats Sandstone of the Tonto Group.
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. 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 ...
Because the Glass Buttes complex has abundant, high-quality obsidian, the Bureau of Land Management has reserved 36 square miles (93 km 2) as a free-use area where the public can gather obsidian for private use. No permits are required; however, individuals can only remove 250 pounds (110 kg) of obsidian per year.
Edziza obsidian is a naturally formed volcanic glass found at the Mount Edziza volcanic complex in northwestern British Columbia, Canada. It occurs in at least four geological formations of the volcanic complex and was widely used by indigenous peoples during the pre-Columbian era .
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Obsidian from the Coso Volcanic Fields was heavily exploited by Native American Coso People to make knives, projectile points, and the like (Hughes 1998). The chief period of exploitation was between approximately 3000 and 1000 years ago, when people mined obsidian by constructing benches in hillsides and digging deep pits to access raw materials (Elston and Zeier 1984; Gilreath and Hildebrand ...