Product Details

First photo is a stock photo of possible interior. While the exterior of these nodules can appear unassuming or rough, they often contain striking interiors characterized by Jasper and UV-reactive chalcedony. Specimen CharacteristicsOrigin: Sierra Mountains, Mexico, particularly the region between Aguascalientes and Zacatecas. Composition: Technically a rhyolite due to its thunderegg nature, this material is highly silicate and often shows brecciation. Visual Features:Exterior: Often beige, brown, or grayish rough nodules.Interior: Can feature vibrant colors including mauve, red, yellow, and black "webbing".Patterns: May contain water banding or botryoidal (grape-like) structures.Hardness: Approximately 5–7 on the Mohs scale. Common Uses This material is popular in lapidary work for creating cabochons, slabs, and polished display specimens. Some collectors value them for their bright green glow under UV light, which is caused by uranyl ion impurities.