5.2" Polished Thunderegg Half (Moss Agate) - Lucky Strike Mine, Oregon

This is a gorgeous "thunderegg" geode half, collected from Oregon. The interior features mossy mineral formations throughout a blue agate, along with white-orange banded agate at the center.

It comes with an acrylic display stand.

Agate is a variety of microcrystalline quartz (chalcedony) that displays translucence and in some cases banding. Agate primarily forms when silica-rich fluids fill pockets within rock and/or fossils, resulting in deposition of the silica along the walls of the rock. This process can result in banding patterns as the composition and impurities of the fluids change over time. These banding patterns can either form as flat layers or rounded layers, depending on the surfaces available for deposition.

Chalcedony var. Agate
Lucky Strike Mine, Ochoco Mtns., Crook County, Oregon
5.2 x 4.7", up to 2.7" thick