Definition of volcanic glass in US English:

volcanic glass


  • another term for obsidian
    • ‘Originally, carvers worked mostly with sharpened stone tools, while details were cut with flakes of volcanic glass (obsidian).’
    • ‘That layer holds minute grains of carbonate rock and volcanic glass.’
    • ‘In 1976 and 1986, the volcano vaulted clouds of ash - a mixture of rock, crystals, and volcanic glass - over Anchorage, coating streets and disrupting air traffic.’
    • ‘They result from nonequilibrium crystallization from the devitrification of volcanic glass, which is postulated to occur at relatively high temperatures following compaction and welding of a hot rhyolitic ash flow.’
    • ‘He uses local tools: a sharp blade for scraping the outside of the skin, a light piece of volcanic glass for reducing it to the appropriate thickness by removing its upper layers, and a needle and thread.’
    • ‘As the lava cools and crystallizes, however, crystals that measure between half a millimeter and tens of millimeters in diameter can retain droplets of ‘melt,’ or still-molten volcanic glass.’
    • ‘And also, within the stone artefacts we found pieces of obsidian and there's no volcanic glass on Norfolk, and this was sourced as coming from the Kermadec Islands.’
    • ‘Even worse is the fact that volcanic glass found in the ash can form hard deposits in the engines and cause failure.’
    • ‘The presence of zeolites such as laumontite, prehnite and pumpellyite indicates diagenetic alteration from original volcanic components of the palaeosols such as volcanic glass.’
    • ‘It turned out to be minute beads of volcanic glass.’
    • ‘Zeolite minerals are diagenetic products formed from the breakdown of volcanic glass and minerals by fluids circulating through the rocks.’
    • ‘I grope blindly and my hand finds a paperweight on the end table, a lump of volcanic glass that Emily picked up on our honeymoon in Hawaii.’
    • ‘Zeolite is a common product of volcanic glass weathering, but may also be related to opal-CT (chert, radiolarian) alteration.’
    • ‘Made up of minute shards of volcanic glass, the ash clouds that drifted across Nebraska from the west were abrasive and dangerous.’
    • ‘Detrital grains of quartz, altered feldspars, laumontite, chlorite, volcanic glass shards and rock fragments make up 5-45% of this horizon.’
    • ‘One of the most significant finds was large quantities of obsidian - a kind of black volcanic glass used like flint for tools - which had come from the Aegean island of Melos.’