Pyrite Rondiceras ammonite from the Volga River, sited between the towns of Ulyanovsk in the north and Saratov in the south. This river region produces some of the best pseudomorph pyritic ammonites known to the world of ammonite collectors. The ammonite has been replaced with pyrite, after calcite mineralisation which has taken place over millions of years. The whole of the Rondiceras ammonite has changed in appearance as pyrite replaces the shell and tissues of the cephalopod which once remained within it's shell. In some specimens, the inner chambers displays rainbow Pyrite which is also wonderfull to see.
Pyrite is a form of Iron Pyrite, commonly known as fools gold, there is nothing foolish about admiring these gems of the earth and every reason to hold them precious, even though they are not as costly as gold. We like to think of them just as highly in the fossil world.
the Pyrite Rondiceras Ammonite is part of the Ammonitida family of marine invertebrates. Once fascinating creatures from the deep ancient oceans and believed to be aggressive creatures like modern day squids we find in the oceans today. With extremely large eyes and remarkable vision they would easily hunt on their prey at great depths, where little or no light penetrates the deep oceans. The Cephalopod would attain its prey using their long tentacles, such as other crustaceans and fish, much as the persisting modern day Nautilus Pompilius which can be found in the Pacific.