igneous
Granite Cobble
Intrusive Igneous Rock (Felsic to Intermediate)
Hardness of 6-7 on the Mohs scale due to quartz and feldspar content; mottled or speckled appearance with colors ranging from pink, gray, white, to black; dull to vitreous luster; massive, crystalline structure; specific gravity typically between 2.65 and 2.75.
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Physical properties
Hardness of 6-7 on the Mohs scale due to quartz and feldspar content; mottled or speckled appearance with colors ranging from pink, gray, white, to black; dull to vitreous luster; massive, crystalline structure; specific gravity typically between 2.65 and 2.75.
Formation & geological history
Formed from the slow cooling and solidification of magma rich in silica beneath the Earth's surface over millions of years. Often shaped into smooth cobbles through water transport in rivers or glacial action.
Uses & applications
Commonly used in construction, architectural building facades, monuments, countertops, paving stones, and landscaping.
Geological facts
Granite is the most common rock of the Earth's continental crust. Its name comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.
Field identification & locations
Easily identified by its distinct interlocking mineral grains (quartz, feldspar, and mica). Found worldwide in major mountain ranges, shields, and cratons, making it a staple for both amateur geology collectors and the stone industry.
