mineral

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), likely massive or granular aggregate

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent cream-yellow color, vitreous to greasy luster, no cleavage, conchoidal fracture, and irregular interlocking crystals. Yellow-brown areas likely reflect limonite/goethite staining or minor feldspar inclusions.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, or fractures, commonly in granitic and metamorphic rocks; the specimen’s exact geological age and locality cannot be determined from the image.

Uses & applications

Common quartz is used in glass, ceramics, engineered stone, abrasives, and electronics; attractive pieces are sold as cabinet or teaching specimens, but this example has modest gem value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure.

Field identification & locations

Identify it by its glassy appearance, lack of cleavage, conchoidal fracture, and resistance to scratching by steel; common worldwide in quartz veins, pegmatites, and placer deposits.