igneous rock

/ˌigniəs rɑk/

Other forms: igneous rocks

Definitions of igneous rock

1. noun

   rock formed by the solidification of molten magma
   types:

   andesite

   a dark grey volcanic rock

   aplite

   light-colored and fine-grained granitic rock consisting chiefly of quartz and feldspars

   groundmass

   (geology) the matrix of fine-grained crystalline material in which larger crystals are embedded

   adesite

   dark greyish extrusive rock

   batholite, batholith, pluton, plutonic rock

   large mass of intrusive igneous rock believed to have solidified deep within the earth

   diorite

   a granular crystalline intrusive rock

   gabbro

   one of a family of granular intrusive rocks

   pegmatite

   a form of igneous rock consisting of extremely coarse granite resulting from the crystallization of magma rich in rare elements

   peridotite

   a dark coarse-grained igneous rock consisting principally of olivine

   rhyolite

   very acid volcanic rock

   volcanic rock

   extrusive igneous rock solidified near or on the surface of the Earth

   porphyritic rock, porphyry

   any igneous rock with crystals embedded in a finer groundmass of minerals

   agglomerate

   volcanic rock consisting of large fragments fused together

   amygdaloid

   volcanic rock in which rounded cavities formed by expanding gas have subsequently become filled with mineral deposits

   dacite

   a grey volcanic rock containing plagioclase and quartz and other crystalline minerals

   basalt

   the commonest type of solidified lava; a dense dark grey fine-grained igneous rock that is composed chiefly of plagioclase feldspar and pyroxene

   volcanic glass

   a kind of natural glass produced when molten lava cools very rapidly

   granite

   plutonic igneous rock having visibly crystalline texture; generally composed of feldspar and mica and quartz

   lava

   rock that in its molten form (as magma) issues from volcanos; lava is what magma is called when it reaches the surface

   tufa, tuff

   hard volcanic rock composed of compacted volcanic ash

   kimberlite

   a rare type of peridotite that sometimes contains diamonds; found in South Africa and Siberia

   type of:

   rock, stone

   material consisting of the aggregate of minerals like those making up the Earth's crust