A large, spectacular, pristine cluster of grey Calcites from the well-known Brushy Creek Mine in Missouri. The condition is excellent, and sparkly Chalcopyrite and Marcasite has coated the recessed areas of the lustrous Calcites, making it exceptionally beautiful (what actually happened is that the original crystal was covered in Chalcopyrite, and then the Calcite began growing again, enveloping the original crystal in some areas and leaving the chalcopyrite exposed in others so this is actually a phantom). Really, the overall aesthetics are stunning and complex - more so in person as the sparkly nature of the coating does not convey well. These are from a major find in the early 1990s..