Colorful Polished Agatized Dinosaur Bone

Description: This is a fine example of section of dinosaur bone from Morocco. When a bone becomes fossilized it is typically a result of permineralization with calcite. Later, a remineralization of calcite by silicates can occur, resulting in a pseudomorph such as this specimen, wherein the calcite is replaced by the silicate mineral agate. Other replacement minerals can be chalcedony (also an agate type), jasper, or opal. Some 35 million years ago during a period of mountain building the region was uplifted and the local strata were infiltrated with heated groundwater rich in silicates resulting in replacement of the calcite in the fossilized bones with silicates, resulting in what are known as “chalcedony pseudomorphs after bone” The varied colors of agatized bone are the result of other minerals that enter the bone in solution along with the silica. The original cellular structure is readily apparent, especially when a cross-section has received a high polish as seen here. This specimen has received such a polish on both the upper and lower surfaces. While it is difficult to ascribe a single type of dinosaur to these specimens, they most likely come from the many large sauropods that roamed the land some 150 million years ago.