mineral

Quartz-rich geode or vuggy quartz vein fragment

Microcrystalline to crystalline quartz, SiO₂, likely with iron-oxide staining and possible chalcedony

AI-generated identification · may be incorrect

White to translucent gray quartz with glassy to waxy luster, irregular cavities, and rusty brown iron-oxide coatings; hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The cavities may contain drusy quartz crystals, though the image does not clearly resolve them.

Identified August 26, 2026More mineral →

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At a glance

Common name: Quartz-rich geode or vuggy quartz vein fragment
Scientific name: Microcrystalline to crystalline quartz, SiO₂, likely with iron-oxide staining and possible chalcedony
Category: mineral
Identified: August 26, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common rough fragment; $30–$150+ if it has attractive drusy crystals, unusual color, or excellent display quality.

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 hydrothermal fluids filled fractures or vesicles, leaving open vugs later lined by quartz; iron-bearing fluids produced the brown staining. Such material can form from Paleozoic to younger volcanic or hydrothermal systems, but the exact age cannot be determined visually.

Uses & applications

Used as a decorative and lapidary stone, specimen material, and occasionally for cabochons or polished pieces; massive quartz is also important industrially in glass, ceramics, and electronics.

Geological facts

The porous appearance reflects dissolved cavities rather than true rock vesicles in many specimens. Acid does not fizz on quartz, helping distinguish it from calcite-bearing material.

Field identification & locations

Common in hydrothermal veins, volcanic cavities, and quartz-rich mineral districts worldwide, including Brazil, Mexico, Morocco, and the western United States. Confirm with a hardness test: quartz scratches ordinary glass, while a steel nail does not scratch it.