2.1" Polished Moctezuma Agate Nodule Half - Chihuahua, Mexico
This is a beautiful, 2.1" wide, polished half of a Moctezuma agate nodule, collected from Chihuahua, Mexico. It features alternating bands of purple, red and yellow agate, and has been cut flat and polished to a glossy finish.
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.