Calcite crystals on matrix coming from the Pyrenees mountains. The main water-clear crystal is a good representative of the local mineralogy. These calcites are sometimes known as "diamond" calcite because of their high grade quality. Watch a video of this specimen by following the Vimeo link below: https://vimeo.com/1168572083/4d68291c96 Ex coll. Bac. Jean-Pierre Bac was a highly active regional field prospector in the departments of Cantal, Aveyron, and Lot from the 1970s through the 2010s. He became a specialist of Curebourse and Enguialès, having developed a close relationship with the family who owned the latter mine. Several specimens from his Curebourse collection were illustrated and published in Le Règne Minéral (1999, issue 29). He also made several remarkable and unusual discoveries in a quarry near Miécaze. Another part of his collection consisted of carefully selected international specimens acquired from French mineral dealers during that period. Ex. J.P. Bac (France)