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  • Pitchstone - Wikipedia
    Pitchstone is a dark coloured, glassy volcanic rock formed when felsic lava or magma cools quickly Since it is a volcanic glass, pitchstone may have a conchoidal fracture Pitchstones may also contain phenocrysts, in which case it is a form of vitrophyre Pitchstone has a resinous lustre, or silky in some cases, and a variable composition Its
  • Pitchstone | volcanic, igneous, obsidian | Britannica
    pitchstone, a volcanic glass with a conchoidal fracture (like glass), a resinous lustre, and a variable composition Its colour may be mottled, streaked, or uniform brown, red, green, gray, or black It is formed by the rapid cooling of viscous lava or magma
  • Pitchstone: Mineral information, data and localities. - mindat. org
    Glassy silicic igneous rocks lacking a conchoidal fracture A dark, resinous volcanic glass
  • Pitchstone, western Scotland - Turnstone
    Pitchstone is a glassy volcanic or subvolcanic intrusive rock, typically with small and often irregular crystallites which nucleated within the melt, but then "quenched" in fanciful forms before growing to their typical crystal habits (shapes) The Corrygills pitchstone forms a sill in the cliff
  • 12 Examples of Volcanic Glass Types You Should Know
    Pitchstone is another dull black (sometimes red, green, gray, or black) volcanic rock with a glassy texture It forms from the rapid cooling of felsic lavas or magma and may appear streaked, mottled, or uniform
  • Pitchstone - Rock Identifier
    Pitchstone is a glassy volcanic rock, similar to obsidian, but duller and with somewhat waxy luster due to its high water content The material is found only in Colorado, USA, and on Arran Island, which is off the coast of Scotland
  • Pitchstone - Encyclopedia
    PITCHSTONE (German Pechstein, from its resemblance to pitch), in petrology, a glassy igneous rock having a resinous lustre and breaking with a hollow or conchoidal fracture It differs from obsidian principally in its rather dull lustre, for obsidian is bright and vitreous in appearance; all pitchstones also contain a considerable quantity of
  • 2014: Pitchstone: The poor cousin of obsidian? - Academia. edu
    Basically, apart from pitchstone’s higher water content, it is an obsidian (or at least a first cousin; see definitions above), and when discussing the extensive prehistoric obsidian exchange networks in the Old World as well as in the Americas, Scottish pitchstone may have a contribution to make
  • Pitchstone Definition Meaning - YourDictionary
    Pitchstone definition: Any of various volcanic glasses distinguished by their dull pitchlike luster
  • Pitchstone - ALEX STREKEISEN
    Pitchstone is a dull black glassy volcanic rock formed when felsic lava or magma cools quickly It is similar to obsidian but is defined by the International Union of Geological Sciences as having a higher water content





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