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Any of several medium- or coarse-grained rocks that consist primarily of plagioclase feldspar and pyroxene. Gabbros are found widely on the Earth and on the Moon. They are sometimes quarried for dimension stone (black granite), but the direct economic value of gabbro is minor. Far more important are the nickel, chromium, and platinum minerals that occur almost exclusively in association with gabbroic or related rocks. Magnetite (iron) and ilmenite (titanium) are also found in gabbroic complexes.
This entry comes from Encyclopædia Britannica Concise. For the full entry on gabbro, visit Britannica.com.