Silicic; glassy
Silicic; fine-grained; likely to contain flow-banding
Intermediate; fine-grained
Mafic; fine-grained
Silicic; medium grained
Intermediate; medium grained
Mafic; medium grained
Silicic; coarse grained
Intermediate; coarse grained
Mafic; coarse grained
Ultramafic; coarse grained
Roughy 66% silica; coarse grained
Silicic; fine-grained; extremely vesicular
Any igneous rock containing two distinct crystal sizes