Mineralogical crystallization begins in a magma at temperatures below 1300°C. then explodes as part of a volcanic eruption, the rest of the liquid will cool very quickly, creating porphyritic rock.

Visual inspection of the dark gray rock suggested that it was probably a fine-grained basaltic igneous rock formed by the crystallization of magma near the planet’s surface.

Igneous rocks contain randomly arranged interlocking crystals. The size of the crystals depends on how quickly the molten magma solidifies and can form extrusive igneous rocks or intrusive igneous ...

The crystal structure of the igneous rock -- not unlike the granite of the Sierra Nevada, but with different composition and much more finely grained -- showed millimeter-sized grains of olivine ...

Characteristics of igneous rocks These rocks are formed when magma solidifies. As the magma cools, mineral crystals will begin to grow. These crystals will grow and interlock to form a hard ...

The origin and evolution of igneous and metamorphic rocks. Emphasis will be on physical and chemical processes, magma transport and crystallization, phase equilibria, development of metamorphic facies ...

Many igneous plagioclases exhibit irregular zoning consisting of corroded cores embayed and surrounded in crystallographic continuity by more sodic plagioclase. Inclusions of this sodic plagioclase ...

A half century later, crystals of the mineral zircon inside a coarse-grained igneous rock fragment collected by Schmitt are giving scientists a deeper understanding about the moon's formation and ...

Visual inspection of the dark gray rock suggested that it was probably a fine-grained basaltic igneous rock formed by the crystallization of magma near the planet's surface.