mineral

Dendritic Agate

Chalcedony (SiO2) with manganese/iron oxide inclusions

Hardness: 6.5-7 (Mohs scale); Color: Translucent gray or white base with tree-like black or brown inclusions; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64.

Hardness: 6
Luster: Waxy to vitreous

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed when mineral-rich groundwater (containing manganese or iron) seeps into cracks in chalcedony or silica-rich rock, depositing precipitates in fern-like patterns. Most deposits are found in volcanic or metamorphic host rocks, with ages varying from millions to hundreds of millions of years.

Uses & applications

Primarily used in jewelry (cabochons), ornamental carvings, and as a popular collector's specimen due to unique 'scenic' patterns.

Geological facts

Despite being called 'dendritic,' these patterns are not organic fossils; they are pure mineral growths known as dendrites. Ancient Greeks associated it with a plentiful harvest and would bury it inতাদের fields.

Field identification & locations

Identify by its translucent body and distinctive branching, moss-like inclusions. Commonly found in Brazil, India, Madagascar, and the USA (e.g., Montana and Oregon). Field collectors look for waxy-textured pebbles in riverbeds or gravel pits.

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