mineral

Milky quartz (likely quartz-rich rock)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to pale blue-gray, translucent, with a vitreous to dull luster and irregular fracture; Mohs hardness 7, no cleavage, and specific gravity about 2.65. The rough, granular appearance may indicate quartz embedded in a quartz-rich host rock.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich igneous fluids and occurs in hydrothermal veins, pegmatites, and metamorphic rocks; individual specimens may range from Precambrian to recent geological ages. The blue-gray color can result from microscopic inclusions or weathering.

Uses & applications

Used in glass, ceramics, engineered stone, electronics, abrasives, and countertops; attractive pieces are sold as inexpensive mineral specimens. These irregular fragments have limited jewelry value unless cut or polished.

Geological facts

Quartz is one of Earth’s most abundant minerals and is the defining mineral of many veins and sandstones. It is commonly confused with calcite, but quartz is much harder and will scratch glass.

Field identification & locations

Common worldwide, especially in Brazil, Madagascar, the United States, and alpine or hydrothermal regions. Confirm by testing hardness against glass and checking that dilute acid produces no fizz; exact identification of the host rock requires a fresh surface or microscopy.