mineral

Orca Agate (Blue Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Dark blue, grey, and white; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Dark blue, grey, and white
Luster: Vitreous to waxy

Identified May 10, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Dark blue, grey, and white; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed through the accumulation of silica-rich groundwater in volcanic rock cavities (geodes/vugs). It is primarily found in Madagascar.

Uses & applications

Used primarily in lapidary arts, jewelry, decorative carvings, and as a popular metaphysical or collector's specimen.

Geological facts

This stone is named 'Orca Agate' due to its distinct white pattern on a dark blue/grey background, which resembles the skin of an Orca whale. It is actually a type of translucent chalcedony rather than a classic banded agate.

Field identification & locations

Identify by its unique 'oceanic' color palette and lack of distinct banding. It often features milky white spots or 'plumes' against a dark base. Common in crystal shops and mineral shows.