Rock Identifier
Orca Agate (Chalcedony (Microcrystalline Quartz, SiO2)) — mineral
mineral

Orca Agate

Chalcedony (Microcrystalline Quartz, SiO2)

Hardness: 6.5-7 (Mohs), Color: Translucent grey, blue-grey, white, and black with wave-like patterns, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness
6
Identified More mineral

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Physical properties

Hardness: 6.5-7 (Mohs), Color: Translucent grey, blue-grey, white, and black with wave-like patterns, Luster: Waxy to vitreous, Crystal Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica from groundwater in cavities within volcanic rocks. The distinct patterns result from differing concentrations of impurities during the layering process.

Uses & applications

Primarily used for ornamental purposes, lapidary art, crystal healing, and as a decorative collector's item in the form of spheres or polished stones.

Geological facts

It is named 'Orca Agate' due to its characteristic black and white swirling patterns that resemble the markings of an orca whale. It is specifically found in Madagascar.

Field identification & locations

Identify by its unique blue-grey and white 'cloud' or 'wave' patterns and high hardness (it will scratch glass). It is exclusively sourced from Madagascar and is popular among crystal enthusiasts for its calming aesthetics.