mineral

Milky quartz pebble

Quartz (silicon dioxide, SiO₂), chalcedonic or massive variety

AI-generated identification · may be incorrect

White to cream, translucent, and glassy to waxy with irregular fractures; quartz has Mohs hardness 7, no cleavage, hexagonal crystal structure, and specific gravity about 2.65. The rounded shape indicates natural or human tumbling, with minor tan iron-oxide staining.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica crystallized from hydrothermal fluids or filled fractures in igneous and metamorphic rocks; the specimen was later weathered and rounded. Quartz occurs from Precambrian rocks to recent stream deposits, so age cannot be determined from the image.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and construction aggregate; attractive pieces are sold as inexpensive cabinet or lapidary specimens.

Geological facts

Milky appearance results from microscopic fluid inclusions, fractures, or impurities scattering light. It may be confused with white calcite, but quartz is substantially harder and does not fizz in dilute acid.

Field identification & locations

Common worldwide, especially in granite pegmatites, quartz veins, river gravels, and metamorphic terrains. Scratch testing with steel or glass can help confirm quartz, though it may damage the specimen.