A volcanic rock of intermediate composition, between silica-poor basalt and silica-rich rhyolite.
A large mass of intrusive igneous rock made mostly of felsic or intermediate rock types.
a volcanic rock that consists of highly vesicular rough-textured volcanic glass.
An igneous, volcanic rock, with aphanitic-aphyric to aphyric-porphyritic texture.
A volcanic rock with gray-white large porphyritic rhombus-shaped phenocrysts of feldspar.
a calcium rich member of the plagioclase solid solution series of feldspar minerals.
A rock-forming mineral belonging to the plagioclase feldspars.
An abundant zeolite mineral that is used commercially.
An extremely hard, dense tetragonal form of silicon dioxide.