Douvilleiceras Posted December 28, 2017 Share Posted December 28, 2017 Ammonites from Madagascar are readily available in rock stores around the world. Dating from the Mesozoic, these ammonites represent an extremely affordable example of prehistoric sealife. In Cretaceous deposits, the iridescent nacre is preserved, encasing interior structures replaced with a variety of minerals. Yet, pyritization (replacement with Iron Sulfide, formula unit FeS2) is uncommon. However, I recently received some pyritized examples from the site - the first I've seen in person. Attached are pictures of some of these interestingly preserved ammonites, including a comparison with Peruvian pyrite (I have a small collection of pyrite from around the world). Polished Example: Sliced Example: Peruvian Comparison: Regards, Jason "Trilobites survived for a total of three hundred million years, almost the whole duration of the Palaeozoic era: who are we johnny-come-latelies to label them as either ‘primitive’ or ‘unsuccessful’? Men have so far survived half a per cent as long." - Richard Fortey, Trilobite: Eyewitness to Evolution. Link to comment Share on other sites More sharing options...
Nimravis Posted December 28, 2017 Share Posted December 28, 2017 Very nice fossils, thanks for posting. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now