mineral

Milky quartz (rough quartz chunk)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to translucent, glassy-to-waxy luster with irregular fracture; Mohs hardness 7, no cleavage, trigonal crystal structure, and specific gravity about 2.65. The porous-looking surface may reflect weathering or attachment to a host rock.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, or igneous and metamorphic rocks; quartz is found in rocks ranging from Precambrian to modern hydrothermal settings. The specimen’s exact locality and age cannot be determined from the image.

Uses & applications

Used extensively in glass, ceramics, electronics, abrasives, engineered stone, and construction aggregate; attractive translucent pieces are sold as inexpensive mineral specimens.

Geological facts

Milky appearance results from microscopic fluid inclusions, fractures, or impurities scattering light. Quartz is one of Earth’s most abundant and durable minerals.

Field identification & locations

Test with a steel file or knife: quartz should resist scratching; it can scratch ordinary glass. Confirm with conchoidal fracture and lack of cleavage, while distinguishing it from calcite, which is softer and effervesces in dilute acid.