mineral

Plume Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: Cream, white, and translucent gray with plume-like inclusions, Luster: Waxy to vitreous, Crystal Structure: Trigonal (cryptocrystalline), Cleavage: None, SG: 2.58-2.64

Hardness: 6

Identified May 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic or sedimentary environments where silica-rich groundwater fills cavities (vugs) in host rock, depositing layers of chalcedony with mineral inclusions that resemble feathers or plumes.

Uses & applications

Used primarily in lapidary arts for jewelry cabochons, ornamental carvings, and as a popular specimen for rock collectors.

Geological facts

Unlike 'moss agate' which has dendritic mineral patterns, plume agates are defined by thicker, billowy inclusions that look more like feathers or clouds. Famous varieties include Graveyard Point and Priday Plume.

Field identification & locations

Identify by its waxy texture, translucency, and distinct internal plume patterns. Commonly found in basaltic lava flows and desert regions including Oregon, Idaho, and Mexico.