Hornblende gabbro

Hornblende gabbro is an intrusive rock similar to normal gabbro. In the QAPF classification it falls within the gabbro field, in which quartz makes up 0% to 5% of the QAPF mineral fraction, plagioclase makes up 90% or more of the total feldspar content, and the plagioclase is calcium-rich. Hornblende gabbro is distinguished from other subtypes of gabbro by having a composition almost entirely of plagioclase and hornblende, with olivine and pyroxene each making up less than 5% of its mineral content.