Pisolite

Photographed by Michael P. Klimetz

Orbicular Silica

Malheur Lake

Harney County

OREGON

Photographed by Michael P. Klimetz

Orbicular Silica

Malheur Lake

Harney County

OREGON

Photographed by Michael P. Klimetz

Orbicular Silica

Malheur Lake

Harney County

OREGON

Photographed by Michael P. Klimetz

Orbicular Silica

Malheur Lake

Harney County

OREGON

A pisolite is a sedimentary rock made of pisoids, which are concretionary grains. Pisoids are typically comprised of calcium carbonate but can also be comprised of silica, oxide and carbonate minerals. Pisoids resemble ooids, but are in excess of 0.2 cm in diameter. Pisoid grains are approximately spherical and have concentric layers up to 1.0 cm in diameter. The name derives from the Greek word for pea. Bauxites, limonites and siderites often have a pisolitic structure.

Photographed by Ulf Thewalt

Orbicular Silica with Chalcedony Cement

Malheur Lake

Harney County

OREGON

12 cm

Photographed by Ulf Thewalt

Orbicular Silica with Chalcedony Cement

Malheur Lake

Harney County

OREGON

1.8 cm