During fossilization, agate (quartz) seeps between the cells over millions of years and replaces the cell structures causing variations in hardness and colour, affecting bone fragments in unique ways. These polished remains of dinosaur bone have preserved exceptionally well and given great insight into the dinosaurs vascular system. Found in the Badlands of Utah, America and from the Cretaceous era, approximately between 125,000,000 - 165,000,000 million years ago.
The Badlands of the southwest of North Dakota close to the Montana border is a series of gullies and buttes of the Dakotas and is the home of the Hell Creek Fossil Formation, one of the richest fossil dinosaur deposits in the world. These fossil deposits were laid down during the Jurassic and Cretaceous period by rivers flowing eastward through swamps to an inland sea that ran from Canada to the Gulf of Mexico, Hell Creek stone dates back to the end of the age of dinosaurs in the Cretaceous period.
High-quality agate dinosaur bone, these interesting tumbled bespoke paperweights have been polished to reveal the complex and vibrant colours of the fossilised bone tissue and its structure. The process of mineralisation has taken approximately a million years.