These drusy pyritised ammonites are from the Volga area in Russia and just a superb example of how the ingress of different minerals can give a beautiful rainbow of colours – a magical visual effect of the fine shimmering crystals.
Now sadly extinct these species were alive approximately 200 million years ago and they became extinct at about the same time as the dinosaurs roughly 65 million years ago.
Rainbow pyritisation can also form on stones and Septaria and are referred to as Drusy (or Druzy) these are much prized for use in jewellery.
When split it looks like they have been plated with brass but actually this is just the Pyrite (polished) which has ingressed into the body of the Ammonite.
Fossil hunting on the banks of the Volga in the Ulyanovsk area of Russia (formerly Simbirsk) usually takes place in the summer for obvious reasons!
Here are two more of these beautiful drusy rainbow pyritised ammonites from my collection.
More information on Ammonites in general is on one of my Fossils Information Pages.
Charlotte
© Copyright Charlotte M Bailey 2013
PS just because they are so beautiful here are a few more images (do click on the images to get a much better view) …
