Ammonite Rondiceras Fossil | Natural Pyritized Fossilized | Upper Jurassic | Mikhailov, Riazan Region, Russia | SO24
$25.00 CAD
Out of stock
A superb example of pyritized ammonites of the genera Kosmoceras, Quenstedticeras and others of the Callovian Stage (161 m.y.a) deposits of Russia. The high degree of preservation of natural mother-of-pearl shell makes it appear to be preserved as fire opal. This is a consequence of light passing through the various layers of aragonite and conchiolin deposited by the ammonite in life. The lack of acidity in the depositional environment allowed them to be preserved as you see here. The environment was also anoxic, leading to formation of Iron Pyrite (Fool's Gold).
Name: Rondiceras tschefkini Ammonite
Age: Upper Jurassic
Location: Mikhailov (Riazan Region), Russia
Dimensions: 22x17 mm / 0.9x0.7 inches
Weight: 3.45 grams / 0.12 oz
Ammonite Rondiceras Fossil | Natural Pyritized Fossilized | Upper Jurassic | Mikhailov, Riazan Region, Russia | SO24
A superb example of pyritized ammonites of the genera Kosmoceras, Quenstedticeras and others of the Callovian Stage (161 m.y.a) deposits of Russia. The high degree of preservation of natural mother-of-pearl shell makes it appear to be preserved as fire opal. This is a consequence of light passing through the various layers of aragonite and conchiolin deposited by the ammonite in life. The lack of acidity in the depositional environment allowed them to be preserved as you see here. The environment was also anoxic, leading to formation of Iron Pyrite (Fool's Gold).
Name: Rondiceras tschefkini Ammonite
Age: Upper Jurassic
Location: Mikhailov (Riazan Region), Russia
Dimensions: 22x17 mm / 0.9x0.7 inches
Weight: 3.45 grams / 0.12 oz
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