- pitchstone
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a natural glass, that is rich in microscopic crystallites, formed by the rapid cooling of lava or magma
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pitchstone
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Pitchstone — is a dull black glassy volcanic rock formed when lava cools swiftly. It is similar to but coarser than obsidian.The ridge of An Sgurr on the Isle of Eigg was originally formed as a lava flow in a valley. Pitchstone is very resistant to erosion … Wikipedia
Pitchstone — Pitch stone , n. (Geol.) An igneous rock of semiglassy nature, having a luster like pitch. [1913 Webster] … The Collaborative International Dictionary of English
Pitchstone — Pitchstone, so v.w. Pechstein … Pierer's Universal-Lexikon
pitchstone — [pich′stōn΄] n. [calque of Ger pechstein < pech (< L pix), PITCH1 + stein,STONE] a volcanic glass that somewhat resembles pitch and has a higher percentage of water than obsidian or other glassy rocks … English World dictionary
pitchstone — /pich stohn /, n. a glassy volcanic rock having a resinous luster and resembling hardened pitch. [1775 85; trans. of G Pechstein. See PITCH2, STONE] * * * ▪ natural glass a volcanic glass with a conchoidal fracture (like glass), a resinous… … Universalium
pitchstone — noun Geology a dull vitreous rock resembling hardened pitch, formed by weathering of obsidian … English new terms dictionary
pitchstone — /ˈpɪtʃstoʊn/ (say pichstohn) noun a glassy igneous rock having a resinous lustre and resembling hardened pitch. {pitch2 (noun) + stone, translation of German Pechstein} …
pitchstone — n. obsidian etc. resembling pitch … Useful english dictionary
An Sgurr (Eigg) — Infobox Mountain Name = An Sgurr Photo = Eigg.AnSgurr.Canthusus.jpg Caption = The Nose of Sgurr, seen from the southeast Elevation = 393 m (1289 ft) Location = Eigg, SCO Prominence = 393 m Parent peak = none HP Eigg Coordinates = Topographic OS… … Wikipedia
Owyhee Dam — View from the north Location Malheur County, Oregon Coordinates … Wikipedia
