mineral

Milky quartz (possibly iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to pale honey-yellow, with vitreous to waxy luster and irregular conchoidal fracture. It lacks cleavage and has a hexagonal crystal structure, though this specimen is rounded and massive.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms in igneous and metamorphic rocks, hydrothermal veins, and pegmatites when silica-rich fluids or melts crystallize. Its precise geological age cannot be determined from the image; iron staining likely caused the yellow coloration.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and engineered stone; attractive pieces are collected or used decoratively. This rough specimen has modest commercial value.

Geological facts

Milky appearance results from microscopic fluid inclusions, fractures, or mineral impurities scattering light. Quartz strongly resists scratching by ordinary steel and is widespread in Earth’s crust.

Field identification & locations

Confirm by testing whether it scratches glass but not by a steel knife, checking for conchoidal fracture, and observing no cleavage; calcite would be much softer and fizz in acid. Common worldwide, especially in quartz veins, granites, and pegmatites.