igneous
Dark, coarse-grained igneous rock (possibly gabbro)
Gabbro, a coarse-grained mafic intrusive rock; identification is tentative from the photo
AI-generated identification · may be incorrectDark gray to black with conspicuous pale mineral grains and an interlocking crystalline texture. Likely dominated by plagioclase feldspar and pyroxene; Mohs hardness about 6, vitreous to dull luster, no cleavage as a whole rock, and specific gravity roughly 2.9–3.1.
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Physical properties
Dark gray to black with conspicuous pale mineral grains and an interlocking crystalline texture. Likely dominated by plagioclase feldspar and pyroxene; Mohs hardness about 6, vitreous to dull luster, no cleavage as a whole rock, and specific gravity roughly 2.9–3.1.
Formation & geological history
Likely formed by slow cooling of mafic magma underground, allowing visible crystals to grow; such rocks occur in crust ranging from ancient to geologically recent.
Uses & applications
Gabbro is used as crushed aggregate, road stone, and building or dimension stone; this small rough specimen is mainly suitable for collecting.
Geological facts
Gabbro can resemble diorite or other dark crystalline rocks; mineral proportions and a fresh broken surface help distinguish them.
Field identification & locations
The coarse interlocking grains and dark color support a mafic intrusive identification, but the photo alone cannot confirm it. Gabbro is common in layered intrusions and oceanic crust; a hand lens and mineral testing can improve identification.
