mineral

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), likely partially translucent massive quartz

AI-generated identification · may be incorrect

Typically Mohs hardness 7, white to translucent with a vitreous luster; lacks obvious cleavage and commonly shows irregular conchoidal fracture. The yellow-brown central coloration is consistent with iron-oxide or clay staining, though the photo alone cannot exclude calcite or chalcedony.

Identified September 14, 2026More mineral →

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Physical properties

Formation & geological history

Quartz commonly crystallizes from silica-rich hydrothermal fluids or forms in cavities and veins, often in igneous and metamorphic rocks. Its age may range from recent vein growth to hundreds of millions of years, depending on host rock.

Uses & applications

Used for glass, electronics, abrasives, and ornamental specimens; attractive translucent pieces may be tumbled or displayed. This specimen appears mainly collectible rather than gem grade.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric. A glass-scratch test can help distinguish it from softer look-alikes, but it may damage the specimen.

Field identification & locations

Common worldwide, especially in quartz veins, granite pegmatites, and metamorphic terrains. Confirm with hardness, lack of cleavage, and acid testing: quartz does not fizz in dilute hydrochloric acid, whereas calcite does.