Reviews
2.3" Polished Cold Mountain Thunderegg (Half) - Mexico
This is a beautiful, polished Cold Mountain thunderegg specimen collected from the Sierra Mountains of Mexico. The face of this specimen has been polished to a glossy finish and the back half is still in its raw form. This nodule half would make a wonderful addition to any agate/jasper collection.
It comes with a floating frame display case.
About Cold Mountain Thundereggs
Cold Mountain thundereggs are distinctive volcanic nodules from Mexico, prized for their colorful interiors and intricate agate patterns. When cut and polished, they commonly reveal contrasting bands and plumes of chalcedony and agate in shades of white, cream, gray, red, orange, and brown. Many specimens display dramatic star-like or irregular central cavities, sometimes lined or completely filled with translucent agate and crystalline quartz. Because the internal fractures and mineralization developed differently in each nodule, no two thundereggs exhibit exactly the same pattern.
These thundereggs formed within silica-rich volcanic rocks, where gas cavities and fractures provided spaces for mineral-rich fluids to circulate. Over time, repeated episodes of silica deposition filled these openings with layers of chalcedony, agate, and occasionally quartz crystals. The relatively plain, weathered exterior of an uncut Cold Mountain thunderegg can give little indication of the complex patterns hidden within, making polished cross sections particularly striking examples of Mexico's volcanic lapidary material.
Cold Mountain thundereggs are distinctive volcanic nodules from Mexico, prized for their colorful interiors and intricate agate patterns. When cut and polished, they commonly reveal contrasting bands and plumes of chalcedony and agate in shades of white, cream, gray, red, orange, and brown. Many specimens display dramatic star-like or irregular central cavities, sometimes lined or completely filled with translucent agate and crystalline quartz. Because the internal fractures and mineralization developed differently in each nodule, no two thundereggs exhibit exactly the same pattern.
These thundereggs formed within silica-rich volcanic rocks, where gas cavities and fractures provided spaces for mineral-rich fluids to circulate. Over time, repeated episodes of silica deposition filled these openings with layers of chalcedony, agate, and occasionally quartz crystals. The relatively plain, weathered exterior of an uncut Cold Mountain thunderegg can give little indication of the complex patterns hidden within, making polished cross sections particularly striking examples of Mexico's volcanic lapidary material.
$22
SPECIES
Chalcedony var. Agate/Jasper
LOCATION
Sierra Mountains, Mexico
SIZE
2.3 x 1.9", up to 1" thick
CATEGORY
ITEM
#373353
