Fossilized ammonite half which reveals the internal chambers lined with calcite crystals. The ammonite has been internally replaced by calcite with small areas showing its original mother-of-pearl iridescent outer shell. This is a complete ammonite sliced and polished to expose the internal cavities now lined with calcite microcrystals. These pieces are from the Late Cretaceous age (about 70 -75 million years). Stock photo shown, you will receive a similar item.