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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. Workers from the Weyerhaeuser Timber Company were ...
Obsidian (/ əbˈsɪdi.ən, ɒb -/ əb-SID-ee-ən ob-) [5] is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. [6] Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminum, sodium, and potassium.
Obsidian projectile point.. Obsidian is a naturally formed volcanic glass that was an important part of the material culture of Pre-Columbian Mesoamerica.Obsidian was a highly integrated part of daily and ritual life, and its widespread and varied use may be a significant contributor to Mesoamerica's lack of metallurgy.
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 ...
Volcanic glass is the amorphous (uncrystallized) product of rapidly cooling magma. Like all types of glass, it is a state of matter intermediate between the closely packed, highly ordered array of a crystal and the highly disordered array of liquid. [1] Volcanic glass may refer to the interstitial material, or matrix, in an aphanitic (fine ...
Pleochroism is an extremely useful tool in mineralogy and gemology for mineral and gem identification, since the number of colors visible from different angles can identify the possible crystalline structure of a gemstone or mineral and therefore help to classify it. Minerals that are otherwise very similar often have very different pleochroic ...
Aqeeq, akik or aqiq (Arabic: العقيق) means quartz in Arabic, and agate in Turkish, however in the context of rings usually refers to a ring set with a chalcedony stone. Well-known types of chalcedony are carnelian, agate, and onyx. It is considered a semi-precious gem stone, and rings set with golden-orange variety of carnelian or sard ...
Distinctively black in color, obsidian from the Chayal beds found at sites throughout the Lowlands as well as the Southern Maya Area supports this assumption, although the specifics of control, whether formally under Kaminaljuyu's hegemony or more informally representing a vital material resource whose wealth accrued to the city more or less in ...