metamorphic

Iron-stained quartz-rich metamorphic rock (probable quartzite or hydrothermal vein rock)

Quartz-dominant rock; chiefly SiO₂, with iron oxides/hydroxides and minor sulfide minerals

AI-generated identification · may be incorrect

Gray to bluish-gray, massive and unevenly fractured, with white quartz patches and rusty brown iron staining; likely hardness 6.5–7, vitreous to dull luster, no obvious cleavage, and specific gravity around 2.6–2.8. The rounded dark areas may be altered sulfides or iron-rich inclusions.

Identified September 6, 2026More metamorphic →

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At a glance

Common name: Iron-stained quartz-rich metamorphic rock (probable quartzite or hydrothermal vein rock)
Scientific name: Quartz-dominant rock; chiefly SiO₂, with iron oxides/hydroxides and minor sulfide minerals
Category: metamorphic
Identified: September 6, 2026
Method: Standard

AI Estimated Value

About $5–$30 as an unattributed specimen; roughly $30–$150 if locality, attractive mineralization, or confirmed ore minerals add collector interest.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Likely formed when silica-rich fluids filled fractures and/or metamorphosed a quartz-rich protolith, with later oxidation producing the brown staining. Precise age and locality cannot be determined from the photograph; such rocks range from Precambrian to younger hydrothermal systems.

Uses & applications

Usually a collector specimen or field sample; massive quartzite can be used as aggregate, dimension stone, or abrasive, but this irregular piece has little commercial use. Valuable metallic minerals would require chemical or laboratory testing.

Geological facts

A white streak and glass-scratching hardness test would support abundant quartz; a metallic streak, magnetism, or visible sulfide crystals could indicate ore minerals. The turquoise-blue patch may be surface staining, copper mineralization, or an artifact, so it should not be identified confidently from the image alone.

Field identification & locations

Common in metamorphic belts and mineralized vein districts worldwide. Test with a steel file or glass, inspect a fresh fracture with a loupe, and use streak, magnetism, acid, or assay tests to distinguish quartzite from ore-bearing vein rock.