Earth Treasures: Thundereggs
By Chisom Ibemere
Thundereggs are geological formations which consist of jasper-filled cavities within volcanic rocks. It is a nodule like rock which is formed within rhyolitic volcanic ash.
The term “thunderegg” is believed to have originated from Native American folklore, which associated these rocks with the sound of thunder. Thundereggs are global in occurrence in various volcanic regions.
Thundereggs are found in different locations across the globe which may include the United States (Oregon, California, Arizona), Mexico, Germany, Australia, Brazil, and Morocco. They are found in association with volcanic rocks such as rhyolite, basalt, and andesite.
Thundereggs are primarily used for lapidary purposes. When cut and polished, the agate or jasper-filled cavities display beautiful patterns, colors, and unique formations.
They can be used in creating cabochons, beads, pendants, and other jewelry items. Thundereggs are also popular among collectors due to their unique aesthetic qualities.
Thundereggs are made up of a variety of minerals basically chalcedony, agate, and jasper. They shows a wide range of colors, including various shades of red, orange, yellow, brown, white, and sometimes bluish hues.
Thundereggs are typically opaque, but some sections may be translucent. Their hardness varies depending on the composition, usually ranging between 6.5 and 7 on the Mohs scale.
The value of thundereggs depends on factors such as their size, quality, color, pattern, and rarity.
Large and high-quality specimens with unique patterns and vibrant colors tend to have higher values in the market. The market value and demand for thundereggs can also vary based on trends among collectors and lapidary enthusiasts.