21663 - Great Collection of 25 Cretaceous Pyritized Ammonites Unidentified Trilobites ScienceDaily

ScienceDaily

The total mass of meteorite pieces recovered from the bottom of Chebarkul lake was therefore ~640 kg

Ischyrhiza

this and the other secondary minerals denote the alteration suffered by the sample

suggests that it belonged to the Elosuchus genus

21663 - Great Collection of 25 Cretaceous Pyritized Ammonites Unidentified Trilobites ScienceDailyPrecious lot of pyritized ammonites! Different species present! It is naturally pyritized. It has undergone a taphonomic process of permineralization in Iron Sulfide (Pyrite). Permineralization is a process of fossilization in which mineral deposits form internal casts of organisms.