mineral

Orca Agate (Chalcedony)

Silicon Dioxide (SiO2) with inclusions

Hardness: 6.5-7 (Mohs); Color: Blue, grey, and white; Luster: Vitreous to waxy; Crystal structure: Hexagonal (Trigonal monocrystalline); Cleavage: None (Conchoidal fracture); Specific gravity: 2.58–2.64

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

Identified March 25, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in volcanic rock cavities (gas bubbles) through the precipitation of silica from groundwater over millions of years. This specific variety is primarily sourced from Madagascar.

Uses & applications

Predominantly used for ornamental purposes, lapidary carvings (towers/points), and metaphysical collecting. Hardness makes it suitable for cabochons and jewelry.

Geological facts

Named 'Orca Agate' due to its colors resembling an Orca whale. It is a variety of chalcedony that often features translucent pockets and opaque white 'banding' or patches.

Field identification & locations

Identify by its distinctive blue-grey and white patterns. In the field, look for volcanic basalt or rhyolite host rocks. This specific specimen has been cut and polished into a 'tower' or 'obelisk' shape.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral