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Product Description
Mushroom Jasper Thunderegg Polished Rock Geode Blue Agate
Lovely Mushroom Jasper thunderegg sliced and polished on one face, rough everywhere else.
It is 3.1 inches by 3 inches and .89 of an inch thick.
Mushroom Jasper, also known as Mushroom Rhyolite, is found in La Paz County, Arizona (northwest of Phoenix).
Though named jasper, it is actually a highly silicated orbicular rhyolite.
It was named Mushroom Jasper because somebody thought its orbs look like mushrooms. The mushroom pattern is usually gray in a brown or reddish matrix and often has quartz or quartz crystals in their centers.
A Thunderegg, is a spherical geode rock with a rough and unappealing surface, but when cut in half is filled with agate, jasper, quartz and/or other minerals. Typically, they are about two to six inches in diameter, although very large ones have been found!
Thundereggs were formed in the rhyolite lava flows and tuffs within the gas or steam pockets that served as molds. The pocket cavity was filled with silica-rich fluids and later solidified and crystallized. Mineral impurities are collected along the bands creating concentric colorful rings.
The name “thunderegg” is believed to have originated from Native American folklore. Native American legend reportedly considers the rocks to be the eggs of the thunderbirds which occupied Mount Hood and Mount Jefferson. Thunder Spirits on the mountains hurled the "eggs" at each other.
