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CMT154pr Cold Mountain Thunderegg Specimen Pair


polished specimen pair featuring shades of brown with tones of red and purple, and small places of concentric, web-like patterning on each half.

Left: 2.25" x 2.5" x 1.5"
Right: 2.25" x 2.5" x 1.25"
10.3 oz together

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.