A light, porous type of pyroclastic igneous rock, formed during explosive volcanic eruptions when liquid lava is ejected into the air as a froth containing masses of gas bubbles.
A gray, crystalline, allotropic form of carbon that occurs as a mineral in some rocks and can be made from coke.
The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO2. It occurs in a variety of forms, both crystalline and amorphous. Found in every environment.
A magnetic mineral, Fe3O4, one of the primary ores of iron. It has also been called lodestone.
A group of igneous and plutonic rocks composed primarily of feldspar and quartz. Usually contains one or more dark minerals, which may be mica, pyroxene, or amphibole.
a type of black glass produced by volcanos
A rock of crystalline limestone.
A hard rock of varied mineral content; volcanic in origin, it makes up much of the Earth's crust.
A fine-grained sedimentary rock of a thin, laminated, and often friable, structure.
An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO₃); it occurs in a variety of forms, both crystalline and amorphous.
A light, porous type of pyroclastic igneous rock, formed during explosive volcanic eruptions when liquid lava is ejected into the air as a froth containing masses of gas bubbles.
A group of igneous and plutonic rocks composed primarily of feldspar and quartz. Usually contains one or more dark minerals, which may be mica, pyroxene, or amphibole.
An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO₃); it occurs in a variety of forms, both crystalline and amorphous.
The most abundant mineral on the earth's surface, of chemical composition silicon dioxide, SiO2. It occurs in a variety of forms, both crystalline and amorphous. Found in every environment.