mineral

Yellow chalcedony (likely citrine-like quartz or calcite)

Microcrystalline quartz, SiO₂; alternatively yellow calcite, CaCO₃

AI-generated identification · may be incorrect

Translucent honey-yellow, waxy to dull luster, rounded and naturally weathered; quartz hardness ~7 with no cleavage, while calcite is softer (Mohs 3) and shows rhombohedral cleavage. The image alone cannot reliably distinguish them.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Yellow chalcedony forms when silica precipitates in cavities and fractures, commonly during volcanic or groundwater activity; calcite forms from carbonate-rich hydrothermal or sedimentary fluids. Age depends on locality, often millions of years.

Uses & applications

Used as a decorative, lapidary, and cabochon material; yellow calcite is mainly a collector specimen and ornamental stone.

Geological facts

A steel knife will not scratch quartz but can scratch calcite; dilute vinegar may fizz weakly on calcite but not quartz. Color can result from iron impurities or inclusions.

Field identification & locations

Common in volcanic cavities, silica-rich veins, limestone settings, and alluvial gravels worldwide. Test hardness and acid reaction, preferably on an inconspicuous spot.