mineral

Dendritic Agate

Chalcedony (Silicon Dioxide) with Manganese or Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs); Color: White, gray, or clear base with dark tree-like inclusions; Luster: Vitreous to waxy; Structure: Microcrystalline; Specific Gravity: 2.58–2.64

Hardness: 6
Color: White, gray, or clear base with dark tree-like inclusions
Luster: Vitreous to waxy

Identified July 8, 2026More mineral →

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Physical properties

Hardness: 6.5–7 (Mohs); Color: White, gray, or clear base with dark tree-like inclusions; Luster: Vitreous to waxy; Structure: Microcrystalline; Specific Gravity: 2.58–2.64

Formation & geological history

Formed when manganese or iron-rich mineralized water seeps into fractures of chalcedony, depositing oxides in branching, tree-like patterns known as dendrites. Usually found in volcanic or metamorphic host rocks.

Uses & applications

Primarily used in lapidary arts as a gemstone for rings, pendants, and beads, and highly valued by collectors for its unique scenic patterns.

Geological facts

Despite being called 'moss agate' or 'dendritic agate', the patterns are not plant fossils (moss) but are actually purely mineral deposits of manganese or iron.

Field identification & locations

Identify in the field by its translucent body with distinct, fractal-like dark 'branches' inside. Common locations include Brazil, India, Madagascar, and the USA (Montana).