mineral

Dendritic Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: honey-yellow, tan, or orange with black/brown inclusions; Luster: waxy; Structure: trigonal/cryptocrystalline; Cleavage: none; SG: 2.60-2.64

Hardness: 6
Color: honey-yellow, tan, or orange with black/brown inclusions
Luster: waxy

Identified June 20, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: honey-yellow, tan, or orange with black/brown inclusions; Luster: waxy; Structure: trigonal/cryptocrystalline; Cleavage: none; SG: 2.60-2.64

Formation & geological history

Formed by the deposition of microcrystalline silica from low-temperature hydrothermal fluids in volcanic rocks or sedimentary environments. These specimens often feature manganese or iron inclusions that create small dark spots or fern-like patterns.

Uses & applications

Used primarily in lapidary work for making jewelry (cabochons), ornamental carvings, and as a popular specimen for collectors.

Geological facts

The tiny black specks resembling seeds or moss are called dendrites, typically composed of manganese oxide. Ancient civilizations used various forms of chalcedony for seals and amulets.

Field identification & locations

Identify in the field by its translucency when held to light, waxy feel, and lack of visible crystalline faces. Commonly found in riverbeds, desert regions, and near volcanic outcrops.

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