igneous petrology Igneous petrology is the study of igneous rocks—those that are formed from magma. As a branch of geology, igneous petrology is closely related to volcanology, tectonophysics, and petrology in general. The modern study of igneous rocks utilizes a ...

, eutaxitic texture describes the layered or banded texture in some extrusive rock bodies. It is often caused by the compaction and flattening of glass

shard Shard or sherd is a sharp piece of glass, pottery or stone. Shard may also refer to: Places * Shard End, a place in Birmingham, United Kingdom Architecture * Dresden Shard, a redesign of the Bundeswehr Military History Museum in Dresden, Germa ...

s and

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...

fragments around undeformed crystals.

See also