crystallization
the formation and growth of a crystalline solid from a liquid or gas
extrusive
fine-grained igneous rock that forms when magma cools quickly at or near Earth's surface
grain size
the size of the grains that make up a rock, which helps to classify the type of rock
igneous rocks
rocks formed by the cooling of molten rock (either magma or lava)
intrusive
a type of igneous rock that generally contains large crystals and forms when magma cools slowly beneath Earth's surface.
magma
molten rock beneath the earth's surface
molten rock
rock that is so hot it is a very thick, slow-moving liquid.
rock cycle
sequence of events in which rocks are formed, destroyed, altered, and reformed by geological processes
pyroclastic rocks
Any rock make up to material ejected explosively from a volcanic vent
porphyritic
rock texture, characterized by large, well-formed crystals surrounded by finer-grained crystals of the same mineral
vesicular
rocks with holes created by expanding gas as magma rose to earths surface
plutonic
Formed underground (also called intrusive). slow cooling = visible crystals.
felsic
describes magma or igneous rock that is rich in feldspar and silica and that is generally light in color
mafic
describes magma or igneous rock that is rich in magnesium and iron and that is generally dark in color
clastic
sedimentary rock that forms when rock fragments are squeezed together
pegmatite
A vein of extremely coarse grained granite, crystallized from a water-rich magma in the late stages of solidification, that cuts across a much finer grained country rock. They provide ores of many rare elements, such as lithium and beryllium.
conchoidal fracture
a curved, irregular break