mineral

Chalcedony breccia (possibly agate with drusy quartz)

Microcrystalline quartz, SiO₂, with crystalline quartz and dark matrix/inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent gray, cream, and brown zones with waxy to vitreous luster and sparkling drusy surfaces. Quartz has trigonal crystal symmetry, lacks cleavage, and has conchoidal fracture; the irregular shape appears naturally weathered or broken.

Identified September 11, 2026More mineral →

Explore Chalcedony breccia (possibly agate with drusy quartz) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Chalcedony breccia (possibly agate with drusy quartz)
Scientific name: Microcrystalline quartz, SiO₂, with crystalline quartz and dark matrix/inclusions
Category: mineral
Identified: September 11, 2026
Method: Standard

AI Estimated Value

Approximately $10–$60 for an ordinary hand specimen; $75–$200+ if unusually attractive, well-polished, or locality-documented.

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

Silica-rich groundwater deposited chalcedony and quartz in cavities or fractures, later incorporating angular dark fragments to form breccia-like banding. Such material commonly forms in volcanic rocks during the Cenozoic, though the specimen’s exact age and locality cannot be determined visually.

Uses & applications

Used as a lapidary stone, cabochon, carving material, and collector specimen; attractive sections may be polished for display. Common rough pieces generally have modest commercial value.

Geological facts

The glittering areas are likely drusy quartz—tiny quartz crystals coating a surface—while the opaque dark portions may be volcanic or iron/manganese-rich matrix.

Field identification & locations

Identify by testing for quartz hardness, conchoidal fracture, and acid resistance; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Uruguay, Mexico, Madagascar, and the western United States.