mineral

Botryoidal quartz geode

Quartz (SiO₂), likely a chalcedony-lined geode with drusy quartz crystals

AI-generated identification · may be incorrect

White to pale gray, waxy-to-glassy luster with sparkling drusy crystal faces; irregular botryoidal surface and hollow cavity. Quartz hardness Mohs 7, trigonal crystal system, no cleavage, specific gravity about 2.65. Some opaque white areas may be chalcedony or calcite, so visual identification is not fully certain.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater deposits chalcedony and quartz on the interior of a gas cavity or vug, commonly in volcanic rocks. The specimen’s exact age cannot be determined from the photograph.

Uses & applications

Primarily a decorative and collector specimen; cut geodes are used as display pieces and jewelry components. Commercial value is usually modest unless exceptionally large, colorful, or crystal-rich.

Geological facts

The rounded “grape-like” texture is called botryoidal. A vinegar or dilute hydrochloric-acid test can help detect calcite, which fizzes, while quartz does not; avoid damaging valuable material.

Field identification & locations

Likely quartz/chalcedony based on the sparkling cavity and hardness appearance. Geodes are common worldwide, but this is geologically plausible near 59.2°N, 10.0°E only if transported or collected from local cavities/pegmatitic or volcanic material; a regional alternative could be quartz-rich vein material. Estimated value: $10–$50 commonly, potentially $50–$150 for an attractive larger specimen.