English version

obsidian

From Longman Dictionary of Contemporary Englishobsidianob‧sid‧i‧an /əbˈsɪdiən/ noun [uncountable]  a type of rock that looks like black glass
Examples from the Corpus
obsidianA plain black obsidian which the Minoan craftsmen tried may have come from the Siftlik area of Cappadocia.A glass tide tinkled on the hull of the receiver, its echoing obsidian.For example, many early human artifacts, such as arrowheads, are made of obsidian, a volcanic glass.Unlike most volcanic rocks, obsidian does not contain phenocrysts; it is, so to speak, all glassy groundmass.Walls, ceilings, floors were clad in smooth obsidian and jet carved with runes, sacred hexes and texts.I had a friend send me some obsidian blades.A glassy stone beloved by ancient toolmakers, obsidian was found only in two prehistoric spots in Arizona prior to the 1980s.Pre-Columbian cultures in the New World did sophisticated operations, including skull surgery, with obsidian, he added.
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