Rock Identifier
Milky quartz (possibly chalcedony-bearing quartz) (Quartz, silicon dioxide (SiO₂)) — mineral
mineral

Milky quartz (possibly chalcedony-bearing quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically hardness 7 Mohs, white to cream and translucent, with vitreous to waxy luster; lacks cleavage and has conchoidal fracture. The specimen appears massive and weathered, with iron-oxide staining and possible chalcedony or minor feldspar inclusions.

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Physical properties

Typically hardness 7 Mohs, white to cream and translucent, with vitreous to waxy luster; lacks cleavage and has conchoidal fracture. The specimen appears massive and weathered, with iron-oxide staining and possible chalcedony or minor feldspar inclusions.

Formation & geological history

Formed when silica-rich fluids crystallized in fractures, cavities, or veins, commonly in igneous and metamorphic rocks; its precise geological age cannot be determined from the image. Yellow-brown colors likely result from hydrated iron oxides.

Uses & applications

Used for glass, ceramics, abrasives, engineered stone, and decorative specimens; attractive translucent pieces may be cut or polished as ornamental stone. This example appears more suitable for collecting than fine jewelry.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge when mechanically stressed. Its cloudy appearance commonly reflects microscopic fluid inclusions, fractures, or impurities.

Field identification & locations

Look for glassy translucence, hardness sufficient to scratch ordinary glass, no obvious cleavage, and conchoidal fracture; a steel knife should not scratch it. Common worldwide in quartz veins, pegmatites, geodes, and hydrothermal deposits.