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 ...

Like other igneous rocks, the glossy glass originates from ... Because of the lack of crystals in the overall structure, pure obsidian takes on a smooth, glossy shine. However, snowflake patterns ...

Igneous rock is formed by the cooling of molten rock ... causing the minerals that compose the stone to re-form into new crystals. Sedimentary rock is formed by the accumulation of minerals and other ...

Igneous rocks are formed when magma underground or ... sometimes plant or animal material, and also crystals left behind when ...

Igneous rocks close igneous rockIgneous rocks are ... As the magma cools, mineral crystals will begin to grow. These crystals will grow and interlock to form a hard crystalline rock.