igneous
Polished orbicular gabbro tower
Gabbro, likely orbicular/pegmatitic variety; mainly plagioclase feldspar and pyroxene, with possible amphibole, olivine, and magnetite
AI-generated identification · may be incorrectCoarse-grained, dark gray to black, mottled or orbicular texture with a polished glassy-to-waxy luster; Mohs hardness about 6–7, nonporous, with poorly visible cleavage and specific gravity around 2.8–3.2.
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Physical properties
Coarse-grained, dark gray to black, mottled or orbicular texture with a polished glassy-to-waxy luster; Mohs hardness about 6–7, nonporous, with poorly visible cleavage and specific gravity around 2.8–3.2.
Formation & geological history
A slow-cooling intrusive mafic igneous rock crystallized deep within Earth, generally during Precambrian to Phanerozoic plutonic events; the pointed tower is human-cut and polished.
Uses & applications
Used for decorative towers, carvings, countertops, monuments, and collectible lapidary pieces; it has little jewelry value beyond ornamental use.
Geological facts
The specimen’s dark matrix and contrasting rounded patches are characteristic of orbicular or mottled gabbro, though exact naming requires a close view or mineralogical testing.
Field identification & locations
Identify by its coarse interlocking crystals, high density, dark mafic color, and lack of layering or vesicles; common sources include India, Madagascar, Finland, Norway, and parts of North America.
