igneous
Polished orbicular granite (likely larvikite or similar feldspar-rich stone)
Coarse-grained granitoid; likely quartz/feldspar/amphibole-bearing granite, with dark mafic inclusions
AI-generated identification · may be incorrectHardness about 6–7 Mohs; rounded polished surface, pink-tan and gray-black mottling, vitreous to dull luster, interlocking crystalline texture, no obvious cleavage on the surface. The dark rounded patches may be mafic enclaves or orbicules.
Identified More igneous →
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Physical properties
Hardness about 6–7 Mohs; rounded polished surface, pink-tan and gray-black mottling, vitreous to dull luster, interlocking crystalline texture, no obvious cleavage on the surface. The dark rounded patches may be mafic enclaves or orbicules.
Formation & geological history
Slow cooling of silica-rich magma produced the coarse crystals, probably during Precambrian to Phanerozoic plutonic activity; orbicular textures form through unusual crystallization around nucleation centers. Exact identification requires a fresh surface or testing.
Uses & applications
Used as a decorative stone, polished cabochon or worry stone, and occasionally for countertops or architectural slabs. Small polished specimens commonly have modest collecting value.
Geological facts
Its appearance is consistent with orbicular or porphyritic granite, but photographs cannot reliably distinguish it from gabbro, diorite, or other polished granitoids.
Field identification & locations
Look for interlocking feldspar crystals, quartz, and dark amphibole/biotite; a streak, hardness test, and close inspection with a loupe help distinguish it from dyed or resin-coated material. Common sources include Norway, Finland, Madagascar, India, and Brazil.
