Cold Mountain Thunderegg Pairs
Natural sliced Cold Mountain Thunderegg geodes
faces are hand polished for display
Approx 1-2” in
Weighs about 3-5oz per pair
Keep in mind that due to exposure and necessary extraction methods crystals may not have perfect faces/points/edges.
A thunderegg (or thunder egg) is a nodule-like rock, similar to a filled geode, that is formed within rhyolitic volcanic ash layers. They usually contain centres of chalcedony which may have been fractured followed by deposition of agate, jasper or opal, either uniquely or in combination. Also frequently encountered are quartz and gypsum crystals, as well as various other mineral growths and inclusions. Thundereggs usually look like ordinary rocks on the outside, but slicing them in half and polishing them may reveal intricate patterns and colours. [source: Wikipedia]
Cold Mountain thundereggs come from the Sierra Mountains between the cities of Aguascalientes and Zacatecas, Mexico.
When you hear the word thundereggs, most people quickly associate them with baseball size geode-type stones filled with agate. In this case, this material is just a slight bit different. This material looks like a bunch of golf balls and marbles all clustered together in a big muddy clump! Once you cut one open though, you will see all the beauty in it. The rhyolite is full of earthy colors, and the orbs have fractal patterns with rivers of agate running through them. [source: Rock & Gem Magazine]