volcanic glass -
1Volcanic glass — Volcanic Vol*can ic, a. [Cf. F. volcanique, It. vulcanico.] 1. Of or pertaining to a volcano or volcanoes; as, volcanic heat. [1913 Webster] 2. Produced by a volcano, or, more generally, by igneous agencies; as, volcanic tufa. [1913 Webster] 3.… …
2volcanic glass — n. natural glass, as obsidian, formed by the very rapid cooling of molten lava …
3Volcanic glass — A sand grain of volcanic glass under the petrographic microscope. Its amorphous nature makes it go extinct in cross polarized light (bottom frame). Scale box in millimeters. Volcanic glass is the amorphous (uncrystallized) product of rapidly… …
4volcanic glass — a natural glass produced when molten lava cools very rapidly; obsidian. [1830 40] * * * Any glassy rock formed from lava or magma that has a chemical composition close to that of granite. Such molten material may reach very low temperatures… …
5volcanic glass — noun a kind of natural glass produced when molten lava cools very rapidly • Hypernyms: ↑volcanic rock • Hyponyms: ↑obsidian, ↑pitchstone, ↑tachylite …
6volcanic glass — volcan′ic glass′ n. gel a natural glass produced when molten lava cools very rapidly; obsidian • Etymology: 1830–40 …
7volcanic glass — noun Date: circa 1840 natural glass produced by the cooling of molten lava too rapidly to permit crystallization …
8volcanic glass — /vɒlkænɪk ˈglas/ (say volkanik glahs) noun a natural glass produced when molten lava cools very rapidly; obsidian …
9volcanic glass — noun another term for obsidian …
10Volcanic ash — consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions,United States Geological Survey. [http://volcanoes.usgs.gov/Hazards/What/Tephra/tephra.html Tephra: Volcanic Rock and Glass Fragments.] Retrieved… …
