5.2" Polished Cruentus Agate Slice - Kerrouchen, Morocco

Cruentus agate is the trade name for an agate formation that features vibrant red coloration and occurs in small cavities, veins, or seams in rock. Cruentus is Latin for blood-stained or bloody, which is fitting considering the red coloration strongly resembles the color of blood. These seams often occur in areas where the rock has naturally shifted or fractured, creating cavities that fill in with minerals. Seam agates like this collected from Morocco come out of the Atlas Mountain region near Kerrouchen (also spelled Karouchen or Kerrouchene).

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.