igneous
Pegmatitic granite with quartz and feldspar
Granitic pegmatite; chiefly quartz (SiO₂), alkali/plagioclase feldspar, and mica, with possible garnet/tourmaline
AI-generated identification · may be incorrectCoarse-grained, pale gray to pink rock with interlocking quartz and feldspar crystals, uneven fracture, and vitreous-to-pearly luster; quartz hardness ~7, feldspar ~6, mica ~2–3, specific gravity typically 2.6–2.7.
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Physical properties
Coarse-grained, pale gray to pink rock with interlocking quartz and feldspar crystals, uneven fracture, and vitreous-to-pearly luster; quartz hardness ~7, feldspar ~6, mica ~2–3, specific gravity typically 2.6–2.7.
Formation & geological history
A felsic igneous rock crystallized slowly from silica-rich magma, likely in a granite intrusion or pegmatite dike. Its exact geological age cannot be determined from the photograph; such rocks range from Precambrian to recent.
Uses & applications
Used as dimension stone, aggregate, monuments, and landscaping material; attractive pieces may be collected, though this specimen appears ordinary and only modestly valuable.
Geological facts
The very coarse texture indicates slow cooling, allowing large crystals to grow. Pink zones are likely potassium feldspar, gray translucent areas quartz, and dark flakes or patches may be biotite or accessory minerals.
Field identification & locations
Identify it by visible interlocking quartz and feldspar crystals, lack of layering, and inability to scratch quartz with a steel knife. Common worldwide in continental crust, especially near granite bodies and pegmatite dikes.
