4.85" Polished Seam Agate - Kerrouchen, Morocco

Seam agate, also known by the trade name "Vein Agate", is an agate formation that occurs in small cavities, veins, or seams in rock. These seams often occur in areas where the rock has naturally shifted or fractured, resulting in a cavity that fills in with minerals, in this case chalcedony (var. agate). Seam agates collected from Morocco come out of the Atlas Mountain region near Kerrouchen (also spelled Karouchen or Kerrouchene). They typically showcase a wonderful mixture of distinct red, yellow, orange, pink and/or white colored bands of agate, with plumes/mosses that branch outward from the walls of the seam. They occur within basaltic rock, which makes sense considering that natural fracturing occurs as basaltic lava cools.

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, depositing silica within them. 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, known as waterline agate, or as more common rounded layers, depending on the surfaces available for deposition.