These are authentic fragments of agatized dinosaur bone, typically with yellow/red coloration.
During the Early and Middle Jurassic, Utah was mostly desert, occasionally flooded as sea levels rose and fell. The majority of Utah’s dinosaur fossils are Late Jurassic in age. They are found mainly in a rock unit known as the Morrison Formation, which dates to approximately 150 million years ago.
Among the dinosaurs that are most commonly found in Utah is Allosaurus, a carnivorous, bipedal theropod that ranged from 10 to 40 feet in length. Allosaurus was at the top of the food chain and probably preyed on large herbivorous dinosaurs, as well as other smaller predators.
Other dinosaurs found in Utah include Brachiosaurus, a slim-necked herbivore estimated to have been between 59 and 72 ft long, and weighed 28 to 50 metric tons; Stegosaurus, a massive quadruped herbivore characterized by the distinctive kite-shaped upright plates along its backs and spikes on its tails; and many others.
