A black rock, formed when a common type of volcanic lava cools and hardens Basalt is faintly magnetized, in the direction of the magnetic field existing when if first cools
a hard, dense, dark volcanic rock composed chiefly of plagioclase, pyroxene, and olivine and often having a glassy appearance, one of the most abundant forms of igneous rock on earth with more than 90% of all volcanic rock and 90% of basic igneous rock being basalt - BACK>>
A rock of igneous origin, consisting of augite and triclinic feldspar, with grains of magnetic or titanic iron, and also bottle-green particles of olivine frequently disseminated
a dark, mafic, igneous rock, usually fine grained, composed of pyroxene and plagioclase Basalts fill the moon's maria and have some important compositional differences from Earth basalts
Basalt is a type of black rock that is produced by volcanoes. a type of dark green-black rock (basaltes, from basanos , from bhnw). Dark igneous rock that is low in silica content and comparatively rich in iron and magnesium. Some basalts are glassy (have no visible crystals), and many are very fine-grained and compact. Basaltic lavas may be spongy or pumice-like. Olivine and augite are the most common minerals in basalts; plagioclase is also present. Basalts may be broadly classified into two main groups. Calc-alkali basalts predominate among the lavas of mountain belts; the active volcanoes of Mauna Loa and Kilauea in Hawaii erupt calc-alkali lavas. Alkali basalts predominate among the lavas of the ocean basins and are also common in mountain belts
A dark, heavy, fine-grained, extrusive igneous rock consisting almost equally of plagioclase feldspars and ferro-magnesium minerals; most common variety of volcanic rock
The dark, dense, aphanitic, extrusive rock that has a silica content of 40% to 50% and makes up most of the ocean floor Basalt is the most abundant volcanic rock in the Earth's crust
A fine-grained igneous rock dominated by dark-colored minerals, consisting of plagioclase feldspars (a calcium-sodium-aluminum-silicate, usually present in amounts over 50%), and ferromagnesium silicates Basalts and andesites represent about 98% of all extrusive igneous rocks