Distinctive features:  
Colour, granularity, predominance of pyroxene and, often, olivine.

Colour: 
Dark grey, dark greenish-grey to black.

Texture and granularity: 
Coarsely granular, but rarely porphyritic. Sometimes bonded, resembling gneiss.

Composition: 
Mainly pyroxene and plagioclase, with greater amounts of pyroxene than plagioclase or equal amounts of both. Olivine is often present, as well as grains of iorn ore (magnetite and/or ilmenite) and bronze-coloured biotite.

Field associations: 
As plutons and similar large bodies, but not as large as those of granites. Also as large sheets, often containing valuable ore deposits (e.g. Lake Superior deposits).

Varieties:
Olivine gabbro, which is like gabbro, but also has olivine phnenocrysts.

 

Scotland, Scandinavia, Canada, England, Germany, USA (New England, New York , Minnesota, California and lesser amounts in other states).

 

Building industry, monumental since it takes a high polish, as a source of iron, nicket and cooper ores (e.g. Sudbury ores in Ontario, Canada).