igneous
Weathered granite (likely glacial erratic)
Granite; predominantly quartz, feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, pale gray to pink-brown, with a weathered granular texture and subdued vitreous luster. Hardness is about 6–7 Mohs; crystals are interlocking, with no prominent cleavage as a whole, though feldspar and mica may cleave.
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Physical properties
Coarse-grained, pale gray to pink-brown, with a weathered granular texture and subdued vitreous luster. Hardness is about 6–7 Mohs; crystals are interlocking, with no prominent cleavage as a whole, though feldspar and mica may cleave.
Formation & geological history
Granite crystallizes slowly from silica-rich magma deep in the continental crust, commonly during Precambrian to Phanerozoic plutonic events. Its rounded shape and weathering suggest transport and abrasion by glacial ice or water.
Uses & applications
Used widely as crushed aggregate, dimension stone, paving, monuments, and countertops; this piece has mainly educational or decorative value.
Geological facts
The mottled appearance reflects quartz, light feldspar, and darker biotite or hornblende. Surface iron staining and granular disintegration indicate prolonged exposure and chemical weathering.
Field identification & locations
Identify it by visible interlocking mineral grains, abundant pale feldspar/quartz, and a hard, nonlayered texture; a steel knife should not easily scratch it. Common in continental mountain belts and glacial deposits, especially northern North America and Scandinavia.
