igneous
Quartz-rich pegmatite
Granitic pegmatite, composed chiefly of quartz (SiO₂) and feldspar, with possible mica
AI-generated identification · may be incorrectCoarse, irregularly crystalline, pale gray to tan with pinkish patches and a vitreous-to-dull luster. Quartz hardness is 7; feldspar is about 6, and mica about 2–3. The image does not show enough detail to confirm individual minerals or cleavage.
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Physical properties
Coarse, irregularly crystalline, pale gray to tan with pinkish patches and a vitreous-to-dull luster. Quartz hardness is 7; feldspar is about 6, and mica about 2–3. The image does not show enough detail to confirm individual minerals or cleavage.
Formation & geological history
Likely formed as a slowly cooled, silica-rich late-stage intrusion or vein from granitic magma; pegmatites commonly formed during the Precambrian through Phanerozoic. Exact age and locality cannot be determined from the image.
Uses & applications
Pegmatite is collected as a specimen and can host quartz, feldspar, mica, and valuable lithium-, tin-, or gemstone minerals; feldspar and mica also have industrial uses.
Geological facts
Pegmatites are notable for exceptionally large crystals, though this specimen appears weathered and its grains are not clearly resolved.
Field identification & locations
Look for coarse interlocking grains and distinct quartz, feldspar, or mica crystals; confirm with close inspection and hardness tests. Pegmatites occur worldwide, commonly near granite bodies.
