groundmass
noun Date: 1879 the fine-grained or glassy base of a porphyry in which the larger distinct crystals are embedded

New Collegiate Dictionary. 2001.

Look at other dictionaries:

  • groundmass — [ground′mas΄] n. Geol. the small grained matrix in which larger crystals are embedded …   English World dictionary

  • groundmass — /grownd mas /, n. the crystalline, granular, or glassy base or matrix of a porphyritic or other igneous rock, in which the more prominent crystals are embedded. [1875 80; GROUND1 + MASS] * * * …   Universalium

  • groundmass — noun The matrix of fine grained crystalline material in which larger crystals are embedded …   Wiktionary

  • groundmass — n. crystalline base of volcanic rock …   English contemporary dictionary

  • groundmass — noun Geology the compact, finer grained material in which the crystals are embedded in a porphyritic rock …   English new terms dictionary

  • groundmass — ground•mass [[t]ˈgraʊndˌmæs[/t]] n. pet the crystalline, granular, or glassy base or matrix of a porphyritic or other igneous rock, in which the more prominent crystals are embedded • Etymology: 1875–80 …   From formal English to slang

  • groundmass — /ˈgraʊndmæs/ (say growndmas) noun the crystalline, granular, or glassy base or matrix of a porphyry, in which the larger crystals are enclosed …   Australian English dictionary

  • groundmass — noun (geology) the matrix of fine grained crystalline material in which larger crystals are embedded • Topics: ↑geology • Hypernyms: ↑igneous rock • Substance Holonyms: ↑porphyry, ↑porphyritic rock …   Useful english dictionary

  • Cumulate rock — Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group… …   Wikipedia

  • igneous rock — Any of various crystalline or glassy, noncrystalline rocks formed by the cooling and solidification of molten earth material (magma). Igneous rocks comprise one of the three principal classes of rocks, the others being metamorphic and sedimentary …   Universalium

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