metamorphic
Blue quartzite pebble (possibly dyed quartzite)
Quartzite; predominantly microcrystalline SiO₂, with blue coloration from inclusions or treatment
AI-generated identification · may be incorrectHardness about 7 Mohs; opaque blue-gray, fine-grained, and weakly vitreous to waxy when polished. Quartz grains are tightly interlocked, with no obvious cleavage and specific gravity near 2.65; the rounded shape indicates tumbling.
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Physical properties
Hardness about 7 Mohs; opaque blue-gray, fine-grained, and weakly vitreous to waxy when polished. Quartz grains are tightly interlocked, with no obvious cleavage and specific gravity near 2.65; the rounded shape indicates tumbling.
Formation & geological history
Forms when quartz-rich sandstone is recrystallized under heat and pressure, commonly during mountain building; its exact geological age depends on the source formation. Strong, unusually uniform blue color may indicate mineral inclusions or dyeing.
Uses & applications
Used as a decorative stone, polished pebble, cabochon, landscaping material, and occasionally in jewelry; quartzite is also used for aggregate and durable construction stone.
Geological facts
Natural blue quartzite is less common than white, gray, or pink varieties. It should scratch glass and resist a steel knife; dye may concentrate in pores or show color fading under solvents.
Field identification & locations
Common sources include Brazil, India, Norway, and the United States, though provenance cannot be determined from the photograph. Inspect grain texture, test hardness, and use magnification to distinguish it from blue glass or dyed chalcedony.
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