Ammonites were free-swimming mollusks of the ancient oceans, living around the same time that the dinosaurs walked the Earth and disappearing during the same extinction event. They came in a range of sizes, from tiny species only a couple of centimeters across, to large ones reaching over two meters in diameter. The animal would have lived in the last and largest of a chain of spiraled chambers. Filling these chambers with fluid or gas allowed the ammonite to sink like a stone to avoid predators. Perhaps one of the most beautiful of all ammonites is the chambered ammonite. This is an ammonite where the inner chambers of the fossil have been replaced with various types of crystals. These chambers must be painstakingly polished and exposed. In this way, the fossil preparer may provide a glimpse into the inner ammonite fossil, a place that can be covered with beautiful crystals. Of course not all fossil ammonites have crystals on the inside. It is actually quite rare to find crystals inside ammonites. More often, the ammonite will have separated chambers that are filled in with solid rock, or the ammonite will have nothing inside but blank rock. The age of the chambered ammonites is approximately 135 million years old. The pieces are very unusual and rare which makes them true collector items.
