mineral

Chalcedony (Yellow Agate / Carnelian Chalcedony)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness 6.5-7 on the Mohs scale, translucent to waxy luster, yellow to pale amber microcrystalline quartz structure, conchoidal fracture, specific gravity ~2.6.

Identified July 26, 2026More mineral →

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Physical properties

Hardness 6.5-7 on the Mohs scale, translucent to waxy luster, yellow to pale amber microcrystalline quartz structure, conchoidal fracture, specific gravity ~2.6.

Formation & geological history

Formed in low-temperature silica-rich hydrothermal fluids filling cavities or fractures within volcanic or sedimentary rocks, creating distinct fibrous layering.

Uses & applications

Used in lapidary work, jewelry, tumbling, decorative stone carvings, and rock collecting.

Geological facts

Chalcedony is composed of microscopic intergrowths of quartz and moganite. The translucent yellow banding seen here is characteristic of seam agate or agate veinlets.

Field identification & locations

Identified by its waxy luster, hardness (will scratch glass), translucent layer banding, and lack of distinct cleavage. Commonly found in gravel beds, desert rockhounding sites, and volcanic terrains globally.