igneous
Pegmatitic granite
Granite/pegmatite; predominantly quartz (SiO₂), feldspar, and mica
AI-generated identification · may be incorrectCoarse-grained, interlocking white/gray feldspar and translucent quartz with dark mica and possible iron-oxide staining; glassy to pearly luster, Mohs hardness about 6–7, poor/no cleavage as a rock, specific gravity about 2.6–2.7.
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Physical properties
Coarse-grained, interlocking white/gray feldspar and translucent quartz with dark mica and possible iron-oxide staining; glassy to pearly luster, Mohs hardness about 6–7, poor/no cleavage as a rock, specific gravity about 2.6–2.7.
Formation & geological history
A slowly cooled felsic igneous rock, likely a granitic pegmatite formed from water-rich magma in the upper crust, commonly during Precambrian to Phanerozoic intrusive events.
Uses & applications
Used as building and dimension stone, aggregate, and a source of feldspar, quartz, and mica; attractive pieces are collected but this specimen appears ordinary.
Geological facts
Very large crystals develop because pegmatitic melts cool slowly and concentrate water and incompatible elements; accessory minerals may include tourmaline, garnet, beryl, or sulfides.
Field identification & locations
Identify it by its coarse interlocking crystals, abundant pale feldspar/quartz, and scattered dark mica; common in granitic terrains, mountain belts, and pegmatite dikes worldwide. A more specific ID would require a fresh surface or mineral tests.
