3.9" Polished, Coyamito Pseudomorph Agate - Chihuahua, Mexico

This is a fascinating, 3.9" wide Coyamito pseudomorph agate section, collected from Chihuahua, Mexico. The agate formed in a banded pattern, encapsulating pre-existing aragonite crystals. Following agate deposition, the aragonite dissolved away, likely as a result of dissolution, leaving behind these hexagonal cavities that can be seen across the polished face and rough side.

An acrylic display stand is included with this specimen.

Coyamito agate is some of the most beautiful and rare of the Northern Mexican agates. Featuring blues, browns, reds, and even sometimes pink, Coyamito agate is most often found as small geodes.

Agate is a variety of microcrystalline quartz 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 after Aragonite
Chihuahua, Mexico
3.9 x 2.9", up to 1.1" thick