mineral

Milky quartz with iron-oxide staining

Quartz, SiO₂

AI-generated identification · may be incorrect

White to translucent, vitreous to dull luster, irregular fracture and no cleavage; Mohs hardness 7, trigonal crystal structure, specific gravity about 2.65. The brown patches may be iron oxides or inclusions, but cannot be confirmed from the photo.

Identified October 16, 2026More mineral →

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Physical properties

Formation & geological history

Quartz commonly crystallizes from silica-rich fluids in veins and pegmatites, or occurs in many rock types; it formed over a wide range of geological ages. This specimen’s exact formation and age cannot be determined visually.

Uses & applications

Quartz is used in glass, electronics, abrasives, and ornamental objects; this rough piece is mainly of collecting or decorative interest.

Geological facts

Milky appearance results from microscopic fluid or gas inclusions scattering light. Quartz is widespread and forms under many geological conditions.

Field identification & locations

The white, massive appearance and lack of obvious cleavage fit quartz. It is regionally plausible near Portland, Oregon, where quartz occurs in varied rocks and veins; hardness or a glass-scratch test can help confirm it.