This seems to be a porphyritic basalt though the phenocrystic phases, presumably augite, are plucked enough as to be virtually nonexistent. The remainder of the thin section is a glassy groundmass with unoriented microlites. The microlitic phases are probably pyroxenes and plagioclase, though color, relief, birefringence, and extinction angles seem incongruent with these minerals.
According to Western Minerals Inc., this sample is a 'contact rock from sediment immediately above dolerite,â€¦rock with quartz 'spots'â€“probably inverted from tridymite spherulitesâ€“in a matrix of devitrified glass with mullite and cordierite.' Due to the fine-grained nature of the sample, it is difficult to distinguish individual mineral phases in the allotriomorphic, equigranular, microcrystalline groundmass. The only noteworthy features in this thin section are the spherical, slightly coarser grained nodules with orange-brown rims.