Gabbro with quartz/feldspar veins

Dark, coarse-grained, massive rock with black pyroxene/amphibole and pale feldspar or quartz patches; typical hardness about 6–7, vitreous to dull luster, interlocking crystals, and no obvious cleavage in the specimen. Exact identification is limited because the surface is weathered and the image provides no scale or tests.

Gabbro crystallizes slowly from mafic magma deep in the crust, commonly in oceanic crust and layered intrusions; its age may range from Precambrian to recent. The pale material likely formed in late fractures or pockets as silica- and feldspar-rich melt cooled.

Used as crushed aggregate, dimension stone, curbing, and polished architectural stone; attractive pieces are collected but are rarely used as gemstones.

Its dark color reflects iron- and magnesium-rich minerals, while the contrasting pale veins indicate later mineral growth or alteration. A fresh broken surface should reveal a granular texture rather than glassy or layered structure.

Common in continental mafic intrusions and oceanic crust worldwide. A streak, hardness, acid, and close-grained examination can distinguish it from basalt, diabase, or metamorphic amphibolite.