mineral

Quartz geode

Microcrystalline and crystalline quartz (SiO₂), possibly with iron-oxide staining and minor calcite

AI-generated identification · may be incorrect

White to gray, botryoidal and drusy crystalline surface with vitreous luster; quartz hardness is about 7 Mohs, lacks cleavage, and has conchoidal fracture. The brown-red exterior likely reflects iron-stained host rock or weathering.

Identified August 30, 2026More mineral →

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At a glance

Common name: Quartz geode
Scientific name: Microcrystalline and crystalline quartz (SiO₂), possibly with iron-oxide staining and minor calcite
Category: mineral
Identified: August 30, 2026
Method: Standard

AI Estimated Value

Approximately $10–$60 for a small, rough common specimen; larger attractive pieces may bring $75–$200, depending on crystal quality and completeness.

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

A cavity in volcanic or hydrothermal host rock was gradually lined by silica-rich fluids, producing botryoidal chalcedony and later quartz crystals. Exact age cannot be determined visually; geodes form in many volcanic terrains from Paleozoic to recent ages.

Uses & applications

Commonly cut, polished, or displayed as a collector specimen; quartz geodes are also used for décor and occasional lapidary work. This appears more valuable as a natural specimen than as gem material.

Geological facts

The rounded, grape-like texture is called botryoidal quartz or chalcedony. Interior crystals commonly grow inward from cavity walls, often with later mineral layers.

Field identification & locations

Identify by its hollow or layered cavity, glassy quartz crystals, hardness, and inability to scratch quartz with a steel knife; acid testing can help distinguish calcite, though confirmation requires examination or testing. Common in volcanic regions worldwide, including Brazil, Uruguay, Mexico, and the western United States.