mineral

Moss agate (likely plume or dendritic agate)

Chalcedony, microcrystalline quartz (SiO₂), with iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; milky white to translucent, with rusty red-brown plume-like inclusions and a waxy to vitreous luster. Quartz has a trigonal crystal structure, but chalcedony shows no visible cleavage and breaks conchoidally; specific gravity is about 2.6.

Identified October 11, 2026More mineral →

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Physical properties

Formation & geological history

Silica-rich fluids deposited chalcedony in cavities and fractures; iron-bearing inclusions created the branching patterns. Agates form in many geological settings and ages, commonly in volcanic rocks.

Uses & applications

Used for cabochons, beads, ornaments, and lapidary collections; it has no major construction use.

Geological facts

The plant-like patterns are mineral inclusions, not fossils or organic material.

Field identification & locations

Identify by its smooth, waxy quartz surface and internal rusty, branching patterns; agate occurs worldwide, including Brazil, India, and the western United States. The photo alone does not establish the exact agate variety.