Ammonite Fossil Collection, Polished & Iridescent (Auction 2026-06-05, Lot 139)

$321.25

North Africa, Morocco, Devonian to Cretaceous, ca. 409 to 66 million years ago. A collection of eleven ammonite fossils representing multiple species, ranging from a large matrix-embedded specimen with well-defined ribbed sutures to smaller examples displaying vivid opalescent iridescence on their natural exteriors – a phenomenon caused by the preservation of the original aragonite shell. Several specimens have been cut and polished to reveal finely detailed interior chambers with glittering crystalline quartz septae. Size of largest: 2.6″ L x 2″ W (6.6 cm x 5.1 cm)

Provenance: private Colorado, USA collection

Condition: Damaged. Largest is fragmentary and missing outer chambers. Five are cut and polished. Active flaking to iridescent layers, with losses and fissures.