Basalt

Properties
Rock group Igneous
Classification Extrusive/volcanic
Composition Mafic
Texture Aphanitic
Intrusive counterpart Gabbro
Common minerals Plagioclase feldspar
Pyroxenes
Olivine

Basalt GigaPans

Plain ol’ aphanitic black basalt

Amygdular basalt from Cornwall, PA

Precambrian-aged amygdaloidal basalt

Another Precamrian-aged amygdaloidal basalt

Porphyritic vesicular basalt from Mt. Vesuvius

A totally different amygdular basalt

Porphyritic vesicular basalt with olivine

Basalt in Thin Section

Basalt, plane polars

Basalt, crossed polars

Precambrian-aged amygdaloidal basalt, featuring huge euhedral  calcite, in plane polars

Precambrian-aged amygdaloidal basalt, featuring huge euhedral calcite, in crossed polars

Precambrian-aged amygdaloidal basalt, featuring the zeolite mineral laumontite, plane polars

Precambrian-aged amygdaloidal basalt, featuring the zeolite mineral laumontite, crossed polars

And you should definitely take a look at these lunar basalt thin sections imaged by Paul Karabinos.

Basalt, PPL
Basalt, XPL