groundmass
Rock's fine base
Groundmass is the fine-grained or glassy material in which larger crystals are embedded in igneous rock.
When magma cools, some minerals crystallize slowly into visible grains while the surrounding material solidifies more rapidly into this compact matrix: The porphyry showed large feldspar crystals set in a dark groundmass.
Fine-grained volcanic stone
- andesiteIntermediate volcanic rock
- rhyolitePale volcanic igneous rock
- obsidianGlassy igneous rock
- pumiceLightweight volcanic abrasive
scoria · tuff · volcanic · extrusive · intrusive · plutonic · lava · magma
Having microscopic crystal structure
- matrixOrdered numerical arrangement
- fine-grainedComposed of minute particles
- glassySmooth and shiny
- vesicularHaving small sacs
basalt
Fine-grained volcanic stone
pumice · scoria · tuff · volcanic · extrusive · intrusive · plutonic · lava · magma · cooling
microcrystalline
Having microscopic crystal structure
- matrixOrdered numerical arrangement
- fine-grainedComposed of minute particles
- glassySmooth and shiny
feldspar
Silicate mineral group
- pyroxeneRock-forming silicate group
- olivineGreen igneous rock mineral
- quartzCrystalline silicon dioxide
amphibole · mica · silicate · glass · magnetite · apatite · hornblende · biotite
mass, ground, background, underground, grounds, grounded, groundwork, grounding, groundless