mineral

Plume Agate

Silicon Dioxide (SiO2) - Chalcedony Variety

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on Mohs scale. Color: Translucent grayish-pink to beige matrix with pink, brownish, and white feather-like or plume-like inclusions. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific gravity: 2.58-2.64.

Hardness: 6
Luster: Waxy to vitreous

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic host rocks through low-temperature hydro-thermal fluids precipitating silica within cavities and vesicles. The plume inclusions are created by mineral oxides and silicates forming delicate, branching structures before or during silica deposition.

Uses & applications

Popular in lapidary arts for cutting cabs, tumble-polishing, and making jewelry like pendants and rings. Highly sought after by mineral collectors for its unique organic patterns.

Geological facts

Plume agate gets its name from the feathery, flower-like, or plume-like inclusions that appear trapped inside the chalcedony matrix. Distinct variations like Graveyard Point plume agate and Pink Plume agate are famed among collectors.

Field identification & locations

Identified in the field by its waxy luster, conchoidal fracture, hard scratch resistance, and characteristic plume or moss-like internal pattern visible under light. Frequently found in regions with ancient volcanic activity like Oregon, Idaho, and Mexico.