mineral

Chalcedony (Agate/Carnelian-like)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Translucent honey-yellow to milky white, Luster: Waxy to vitreous, Crystal structure: Trigonal (microcrystalline), Cleavage: None (conchoidal fracture), SG: 2.6-2.64

Hardness: 6

Identified July 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a chemical precipitate from silica-rich hydrothermal fluids or groundwater within cavities of volcanic or sedimentary rocks. This specimen shows typical 'chert-like' or chalcedony weathering patterns.

Uses & applications

Commonly used for lapidary work, jewelry (beads/cabochons), and as a collector's specimen. Historically used for making tools and seals.

Geological facts

Chalcedony is a cryptocrystalline form of silica, meaning its crystals are so small they can only be seen under extreme magnification. It has been used by humans for ornament and tools since the Bronze Age.

Field identification & locations

Identify in the field by its waxy luster, translucency, and distinctive conchoidal (shell-like) fracture edges. Commonly found in riverbeds, desert pavements, and volcanic regions worldwide.

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