gemstone

Dendritic Chalcedony (Moss Agate / Aquaprase)

Silicon Dioxide (SiO2) with iron/manganese oxide inclusions

Hardness: 6.5-7 on the Mohs scale. Color: Translucent pale sea-foam green to bluish-green with dark dendritic or spot-like inclusions. Luster: Waxy to vitreous. Crystal structure: Microcrystalline/Cryptocrystalline trigonal quartz. Cleavage: None (conchoidal fracture). Specific gravity: 2.58–2.64.

Hardness: 6
Luster: Waxy to vitreous

Identified July 27, 2026More gemstone →

Explore Dendritic Chalcedony (Moss Agate / Aquaprase) in the encyclopedia →

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Physical properties

Formation & geological history

Formed through low-temperature precipitation of silica-rich fluids in fractures, cavities, or volcanic rocks. The greenish tint often stems from trace elements like nickel or chromium, while the dark specks are manganese or iron oxide dendrites.

Uses & applications

Used primarily as a gemstone in lapidary work, cabochons, polished tumbled stones, beads, and metaphysical/collector specimens.

Geological facts

Microcrystalline quartz gemstones with dendritic patterns have been prized since antiquity. Variations with bluish-green body colors are sometimes commercially traded as Aquaprase or moss chalcedony.

Field identification & locations

Look for a translucent cryptocrystalline body showing waxy luster and internal mossy or spot-like dendritic inclusions. Commonly found in Brazil, Madagascar, India, Montana (USA), and Zimbabwe.

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