Tree Agate
Silicon Dioxide (SiO2) with inclusions of manganese and iron oxides
Rock Type: mineral

Physical Properties
Hardness: 6.5-7 Mohs; Color: White to grey base with deep green dendritic patterns; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (Trigonal); Cleavage: None; Specific Gravity: 2.58-2.64
Formation & Geological History
Formed from volcanic groundwater rich in silica that seeps into cracks and cavities in rocks. The green dendritic patterns are created by the crystallization of manganese or iron oxides during the stone's formation over millions of years.
Uses & Applications
Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular specimen for crystal collectors. It is often used in landscaping or as tumbling material.
Geological Facts
Tree agate is technically a type of chalcedony rather than a true 'banded' agate. It has been used since ancient times as a talisman for agricultural success and prosperity.
Field Identification & Locations
Identify by its opaque white body and mossy green plant-like patterns that do not form circles or bands. Commonly found in India, Brazil, and the USA (Montana). Collectors look for high contrast between the white and green.
Identified on: 4/17/2026
Mode: Standard