Fossil Ammonite Pen Holder – Spathites rioensis, 91 Million Years, Cretaceous of Chihuahua

This desk set features a genuine fossil ammonite, Spathites rioensis, dating to the Middle Turonian stage of the Late Cretaceous, approx. 91 million years ago. Discovered in the Ojinaga Formation of Chihuahua, Mexico, these ammonites are part of the Vascoceratidae family and are prized as index fossils, helping paleontologists date and correlate Turonian marine strata across northern Mexico, New Mexico, and Texas.

The fossil has been cut and polished to reveal its intricate spiral chambers with crystalline mineral deposits. Its shell preserves the highly complex ammonitic suture patterns that mark evolutionary advances in this lineage, which may be linked to the origins of later genera such as Buchiceras. This specimen comes mounted on a polished hardwood base, fitted with a brass plaque engraved with provenance details from the Museo de Paleontología in Delicias, Chihuahua.

More than just decorative, the base serves as a functional desk accessory, fitted with a gold-tone holder and a slot for business cards. A matching wooden pen with brass accents is included, and it can be stored inside the base or displayed upright. The combination of natural history, craftsmanship, and practicality makes this a remarkable conversation piece for collectors, academics, or as a distinguished executive gift.

Condition:
Good overall condition. Fossils display natural mineralization and variations from age. The wooden base is smooth with light handling wear, and the brass plaque remains bright and legible. The included wood-and-brass pen is intact and in working order.

Dimensions:
Overall: 1" x 6.5" x 2 1/4"
Without Pen: 2.5" x 6.5" x 2"
Fossils (each): 2" x 1 3/4" x 7/8"
Overall Weight: 9.6 oz
Includes wooden pen with gold-tone fittings