any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium

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

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

a type of igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture.

a phaneritic texture intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar.

a widely distributed feldspar that forms rocks

rare plagioclastic feldspar occurring in many igneous rocks

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

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

a type of igneous, plutonic (intrusive) rock, of felsic composition, with phaneritic texture.

a phaneritic texture intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar.