volcanic glass

Noun
  1. A kind of natural glass produced when molten lava cools very rapidly (synset 114904928)
    is a type of: volcanic rock - extrusive igneous rock solidified near or on the surface of the Earth
    subtypes:
    • obsidian - acid or granitic glass formed by the rapid cooling of lava without crystallization; usually dark, but transparent in thin pieces
    • pitchstone - dark acid granitic glass
    • tachylite - a basic or basalt glass

Found on Word Lists

Other Searches