1. volcanic rock which resembles granite. gabbro\gab"bro\ , n. [it.] (geol.) a name originally given by the italians to a kind of serpentine, later to the rock called euphotide, and now generally used for a coarsely crystalline, igneous rock consisting of lamellar pyroxene (diallage) and labradorite, with sometimes chrysolite (olivine gabbro). 2. A name originally given by the Italians to a kind of serpentine, later to the rock called euphotide, and now generally used for a coarsely crystalline, igneous rock consisting of lamellar pyroxene and labradorite, with sometimes chrysolite . one of a family of granular intrusive rocks. 3. 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.
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