igneous
Polished granite sphere
Granite, chiefly quartz, alkali feldspar, and plagioclase with dark biotite/amphibole minerals
AI-generated identification · may be incorrectFine- to medium-grained, pale gray with black mineral speckles and a polished surface; hardness about 6–7 Mohs, granular crystal structure, no prominent cleavage as a whole, and specific gravity around 2.6–2.8.
Identified More igneous →
Explore Polished granite sphere in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Fine- to medium-grained, pale gray with black mineral speckles and a polished surface; hardness about 6–7 Mohs, granular crystal structure, no prominent cleavage as a whole, and specific gravity around 2.6–2.8.
Formation & geological history
An intrusive igneous rock crystallized slowly from silica-rich magma deep underground, generally during Precambrian to Phanerozoic mountain-building events. The sphere is human-cut and polished.
Uses & applications
Used for decorative spheres, countertops, monuments, flooring, and construction aggregate; collectible value is usually modest unless the stone has unusual color or provenance.
Geological facts
The black grains are commonly biotite mica or hornblende, while the light grains are feldspar and quartz. Granite’s visible interlocking crystals indicate slow cooling rather than volcanic eruption.
Field identification & locations
Identify it by its hard, speckled, interlocking texture and resistance to scratching; a steel knife usually will not scratch it. Common sources include India, Brazil, China, Scandinavia, and North America.
