This thin section is comprised entirely of glass and aligned plagioclase microlites. A few hematite nodules are found throughout. One weathered biotite phenocrysts can be seen.
This strongly layered rock is also strongly altered and microcrystalline enough for minerals to be indistinguishable. The layering is defined by alternating dark and light lenses. Frequently, elongated, flattened vesicles will have a lighter-colored rim. This thin section has a greasy-looking film on the surface that makes it difficult to focus clearly.
Plagioclase laths in this thin section have a continuous gradation in size from groundmass to phenocrysts. Most are euhedral in shape and this phase makes up roughly 70-80% of the minerals in this sample. Subhedral clinopyroxene makes up the remaining 20-30% of the minerals. The larger, blocky plagioclase is locally zoned and a sieve texture is observable in some grains.