igneous
Quartz-rich pegmatite (milky quartz specimen)
Quartz, SiO₂, likely with feldspar and minor mica
AI-generated identification · may be incorrectHardness about 7 for quartz; white to gray, vitreous to pearly luster, translucent grains, no cleavage, and irregular fracture. The coarse interlocking texture suggests pegmatite rather than a single quartz crystal.
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Physical properties
Hardness about 7 for quartz; white to gray, vitreous to pearly luster, translucent grains, no cleavage, and irregular fracture. The coarse interlocking texture suggests pegmatite rather than a single quartz crystal.
Formation & geological history
A coarse-grained igneous rock formed when silica-rich magma crystallized slowly in a granitic pegmatite vein, typically during the final stages of granite emplacement. Exact age and locality cannot be determined from the photograph.
Uses & applications
Common quartz-rich pegmatite is used as aggregate, silica feedstock, and an educational or decorative specimen; gem value is generally low unless unusually clear or associated with collectible minerals.
Geological facts
Quartz is one of Earth’s most abundant minerals and is chemically resistant, allowing quartz-rich fragments to persist in sediments and soils.
Field identification & locations
Identify it by its very hard, glassy grains that can scratch ordinary glass, combined with coarse white feldspar and possible mica. Common worldwide, especially in granitic regions; typical specimen value is about $5–$25, rising to $30–$100+ for attractive, locality-labeled pieces.
