metamorphic

Blue-gray quartz-rich rock, possibly quartzite or massive quartz

Quartz (SiO₂), likely recrystallized as quartzite

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale blue-gray, translucent to opaque, with a vitreous to waxy luster and no obvious cleavage. The granular, dense appearance is consistent with interlocking quartz crystals, though the image limits certainty.

Identified September 6, 2026More metamorphic →

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Physical properties

Formation & geological history

If quartzite, it formed when quartz-rich sandstone was metamorphosed under heat and pressure, typically during mountain building; its precise geological age cannot be determined visually. If a vein fragment, it formed from silica-rich hydrothermal fluids filling fractures.

Uses & applications

Quartzite is used as durable aggregate, building stone, slabs, and landscaping material; attractive blue-gray pieces may be collected or polished. Common massive quartz has minor ornamental value unless exceptionally clear or vividly colored.

Geological facts

The blue-gray color can result from fluid inclusions, microscopic impurities, or deformation-related defects rather than a distinct blue mineral. Quartz commonly produces irregular conchoidal fractures and resists scratching by ordinary steel.

Field identification & locations

Common in metamorphic terrains and quartz veins worldwide; test by trying to scratch glass, which quartz should readily do, and inspect for fused sandstone grains versus a glassy vein texture. Exact identification would benefit from a fresh surface, hardness test, and specific-gravity measurement.