igneous
Quartz-rich pegmatite
Granitic pegmatite, composed mainly of quartz (SiO₂) with likely feldspar and mica
AI-generated identification · may be incorrectCoarse, interlocking white-to-pale-gray crystals with rusty iron-oxide staining; quartz has Mohs hardness 7, vitreous luster, and no cleavage. The image suggests a quartz-rich, irregularly fractured specimen, but exact minerals cannot be confirmed visually.
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Physical properties
Coarse, interlocking white-to-pale-gray crystals with rusty iron-oxide staining; quartz has Mohs hardness 7, vitreous luster, and no cleavage. The image suggests a quartz-rich, irregularly fractured specimen, but exact minerals cannot be confirmed visually.
Formation & geological history
Likely crystallized slowly from water-rich residual magma in a pegmatite vein or dike; pegmatites formed throughout geologic history, commonly late in granitic intrusions.
Uses & applications
Quartz and feldspar from pegmatites are used in glass, ceramics, and construction; attractive or unusually large crystals may be collected or used decoratively.
Geological facts
Pegmatites can contain exceptionally large crystals and economically important minerals, though this specimen appears mostly quartz-rich.
Field identification & locations
Look for coarse crystals, glassy quartz with conchoidal fracture, and feldspar that breaks along flatter cleavage surfaces. Pegmatites occur in granitic terrains worldwide; this photo alone cannot establish a precise identification or locality.
