mineral
Iron-stained milky quartz
Quartz (SiO₂), locally limonite/goethite-stained
AI-generated identification · may be incorrectTypically Mohs hardness 7, white to honey-brown, vitreous to greasy luster, translucent edges, conchoidal fracture, and no cleavage; the dark patches are likely iron oxides or minor host-rock inclusions. Crystal structure is trigonal, though this specimen is massive rather than visibly crystalline.
Identified More mineral →
Explore Iron-stained milky quartz in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically Mohs hardness 7, white to honey-brown, vitreous to greasy luster, translucent edges, conchoidal fracture, and no cleavage; the dark patches are likely iron oxides or minor host-rock inclusions. Crystal structure is trigonal, though this specimen is massive rather than visibly crystalline.
Formation & geological history
Formed when silica-rich hydrothermal fluids precipitated quartz in fractures or cavities, later acquiring yellow-brown iron-oxide staining through weathering. Exact age and locality cannot be determined from the image.
Uses & applications
Used as a durable silica source, aggregate, abrasives, and ornamental stone; attractive pieces are collected or cut and polished, but this specimen appears mainly lapidary/collecting grade.
Geological facts
Quartz is one of Earth’s most abundant minerals and commonly survives weathering because of its hardness and chemical resistance.
Field identification & locations
Identify by hardness—quartz scratches glass—combined with conchoidal fracture and lack of cleavage; iron staining produces the warm coloration. Common worldwide in veins, geodes, pegmatites, and quartz-rich rocks.
