. CMT148 Cold Mountain Thunderegg Specimen | The Gem Shop, Inc.

CMT148 Cold Mountain Thunderegg Specimen


Cold Mountain Thunderegg polished specimen displays reddish brown, mauve, and black coloring with translucent, blue-grey chalcedony filling in the thunderegg fracture pattern.

5" x 3.5" x 3"

1lb 15oz

Cold Mountain Thundereggs are from the Sierra Mountains in Mexico. The thundereggs can contain water banding and feature red, mauve, or black “webbing.” While technically a rhyolite due to its thunderegg nature, Cold Mountain Thundereggs are highly silicate and feature large amounts of brecciation that has also been filled with silica, so this material takes an exceptional polish, making it ideal for both cabochons and specimens.