A Large, polished Hoploscaphites nicolleti ammonite which brings out the brilliant flashes of red from the aragonite shell material (produces an "opal-like sheen!"). The entire ammonites surface flashs red as your rotate the it (Sorry, it is difficult to capture in a photo.) This ammonite is from the upper Cretaceous, Fox Hills Fm. of So. Dakota. Authenticity guaranteed. A wonderful display piece.
SD10 Size: 3-7/8"
Note - Adding 10 So. Dakota ammonites in December 2020. --> Link to So. Dakota Ammonites