Stomping across the Jurassic floodplains, sauropods were massive dinosaurs. Some genera, like Apatosaurus, grew over 75 feet long and weighed more than 20 tons. With a long neck and a whip-like tail, a sauropod would be a tremendous sight, towering over the smaller dinosaurs of its day.

This specimen is a polished sauropod bone cross-section which has been preserved for millions of years and infused with a brilliant agate. It comes from the Morrison Formation of Utah, one of the most studied fossil beds of the upper Jurassic Period which was once home to a large floodplain ecosystem 150,000,000 years ago. Here, these enormous dinosaurs walked the earth, munching on vegetation to power their massive bodies.

Over tens of millions of years, hard minerals, such as chalcedony and quartz, replaced the original organic material. The result is a beautiful marrow matrix exhibiting incredible detail and rich colors.

Each of these specimens is a showcase piece that our team at Mini Museum has polished by hand. Due to the nature of fossilization, each specimen will have a unique mix of pattern, color, and shape. The pattern seen here was formed from the internal cavities of the dinosaur's bone, which once allowed blood flow. The cavities were filled with vibrantly colored minerals, which differentiates them from the darker bone structure. Every specimen forms the amazing mineral matrix in its own way, like a Mesozoic-era thumbprint.

Since this fossilization process is dependent on groundwater minerals, the geologic makeup of each fossil is different depending on where it was formed. The red colors in many of these specimens indicate that oxidized iron or "hematite" may have been present at the time of fossilization.

Each specimen comes with an informational authenticity card. You can see all currently available polished sauropod bone and Morrison Formation specimens in the collection below!

The stunning pattern seen in these fossils is a combination of biologic and geologic processes over the course of millions of years. A dinosaur begins the fossilization process after its body is buried by sediment. Over time, groundwater can seep into empty spaces within the organism's body, such as the internal structure of a bone.

This groundwater carries minerals that fill in the gaps, eventually leaving a buildup of geologic material. This occurs over an extremely long period of time, millions of years at least. Since the process is so gradual, small and delicate details can be preserved in stone, such as the spongy inside of a dinosaur bone seen here or even the gaps in the cell walls of fossil plants.

This material is also known as "gem bone," as the agatized nature of the fossil makes it both an amazing look into the past and a breathtaking mineral to admire.