Glassy Texture

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Glassy Texture

 

the texture of volcanic rock that consists entirely of volcanic glass or that contains, in addition to volcanic glass, a small number of crystals (phenocrysts) in the groundmass. Glassy texture is most commonly found in rocks that are rich in silica and poor in calcium, magnesium, and iron. The rapid cooling of lava on the earth’s surface is conducive to the formation of this type of texture.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The glassy texture suggests that the lava hardened quickly into rock, at a pace consistent with nonexplosive water-lava interactions.
Because even if it is coloured or transparent, when a thin surface is glazed, the glaze becomes a different layer covering the original glassy texture. On the other hand, water soluble colorants are materials that offer aesthetic qualities which support the texture and semi-transparency qualities of the porcelain.
Along the sides of the flows, the lava has a glassy texture and breaks into telltale hexagonal columns--twin indications that the flows cooled rapidly.