gemstone

Polished moss agate (likely dendritic/mossy chalcedony)

Cryptocrystalline quartz, SiO₂, with green chlorite/iron-manganese inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent gray-green to creamy body with branching moss-like inclusions; vitreous to waxy luster, no visible cleavage, microcrystalline quartz structure, and specific gravity about 2.60–2.65.

Identified August 24, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or fractures, trapping chlorite, hornblende, or manganese-oxide inclusions that create the moss patterns. It commonly formed in volcanic rocks during ancient hydrothermal activity, typically from Paleozoic to Cenozoic settings.

Uses & applications

Used for cabochons, beads, carvings, and inexpensive jewelry; polished pieces are also collected for their scenic patterns.

Geological facts

Despite its name, moss agate is not true agate in every specimen because it often lacks distinct banding. Green inclusions can resemble miniature landscapes, branches, or submerged vegetation.

Field identification & locations

Identify it by its hardness, waxy-translucent chalcedony body, and non-geometric green inclusions; it should not fizz in dilute acid. Common sources include India, Brazil, Uruguay, the United States, and Australia.