5.9" Lustrous Binghamite Agate Slab - Minnesota

Binghamite, also known as "silkstone" or "cuyunite", is a highly sought after variety of agate that is only found near the Cuyuna iron range in Crow Wing County, Minnesota. It often displays vibrant red, orange, and yellow colors and in some cases contains small veins of iron running throughout the agate. Many specimens have chatoyant properties that are similar to tiger's eye. The chatoyance can be attributed to the fibrous hematite and goethite parallel crystal formations that the agate deposits around.

About Agate

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 rocks and/or fossils, depositing the silica along the walls of the rock. This process can result in banding patterns, as the compositions and impurities of these depositing fluids change over time. These banding patterns can either form as flat layers, creating linear patterns known as waterline agate, or as rounded layers, forming more common ring-like patterns. These patterns depend on the surfaces available for deposition.