Ammonite & Abalone Necklace
Ammonite & Abalone Necklace
Ammonites are an extinct group of cephalopods that entered the fossil record 400 million years ago. This necklace is made from a fossil ammonite shell and is inlaid with iridescent abalone material.
The abalone nacre can appear as blue, green, and even violet and shifts color within the light. Each necklace is set into a fine sterling silver backing with an 18" chain.
📸 Ammonite Necklace embedded with Abalone
Ammonites are an extinct group of cephalopods that entered the fossil record 400 million years ago. They survived several mass extinction events, including the Permian–Triassic "Great Dying" which wiped out 96% of all marine species. They finally succumbed during the Cretaceous-Paleogene extinction event 66 million years ago, which also wiped out the dinosaurs.
This necklace is a fossilized shell from an ammonite that has been carefully inlaid with beautiful abalone material. Abalone nacre is an iridescent material produced by molluscs in their inner shells. Also called mother-of-pearl, it smooths the shell and produces beautiful coloration. This gives a stunning shine to the already incredible fossil pendant.
📸 The Necklace lit by shining ammonite shell pieces
Each necklace is set into a fine sterling silver backing and comes with an 18" chain. The pendant measures approximately 1.25" by 1.25", though there can be variation depending on the fossil.
Coloration can vary between necklaces, but you can expect to see blues, greens, and even purples in the ablone. Since this material is irridescent, it will also shift in color as you move it through the light, making it a wonderfully dynamic piece of jewelry.
The necklace comes in a decorative box and includes a small information card about the fossil. The card serves as the certificate of authenticity and can be found underneath the padded lining of the display box.
📸 An artist's depiction of an ammonite swimming through the prehistoric sea
MORE ABOUT AMMONITES
ESTIMATED AGE : c. 110,000,000 years old
A Perfect Spiral
Ammonites are an extinct group of cephalopods which entered the fossil record 400 million years ago. They survived several mass extinction events, including the Permian–Triassic "Great Dying" which wiped out 96% of all marine species. They finally succumbed during the Cretaceous-Paleogene extinction event 66 million years ago, which also wiped out the dinosaurs.
The size of ammonite shells range from sub-centimeter dwarf species to giants nearly three meters in diameter. Most iconic shells exhibit a nearly perfect logarithmic spiral.
The Shine of Abalone
Abalone is an organically produced material which gives off an iridescent shine. When some molluscs grow their shells, they can produce microscopic layers of calcium carbonate that are aligned with slight variations. These mirrors act like tiny mirrors that refract and reflect light. The light rays are split into new colors, giving the impression of a shifting, technicolor surface.
This material is also called nacre and serves a defensive purpose for the animal. It keeps the inside of their shell smooth and strong, making it difficult for parasites or microoganisms to infest them.
📸 A variety of different ammonoid shells
How these creatures lived is of intense interest to science, as ammonites likely played a vital role in the food chain in the ancient seas. Evidence exists to suggest that ammonites were a prime food source for Mosasaurs and fishes, while other studies suggest the bite marks on their remains were created after death by limpets or even by other cephalopods.
Many thousands of distinct species make up the long-lived ammonoid subclass. Though most ammonite shells are the classic spiral, there are also straight and gastropod-like shells and even some shells that are partially uncoiled. The surface of the shells also vary quite widely, from smooth to wildly thorny.
Ammonites were an incredibly diverse and plentiful group of animals that survived for hundreds of millions of years and lived all across the planet. Their rapid diversification and tough, rocky shells means there are many different and easily identifiable species in the fossil record. Because of this, scientists can use them to easily identify the age of other fossils and geologic deposits found in the same layer of the ammonites. They're a welcome sight to the eyes of any inquisitive geologist!
Aside from their complex shells, there is little direct evidence regarding the appearance of ammonites due to the absence of soft tissue fossils. However, many scientists believe ammonites had bodies similar to that of the present-day Nautilus.
📸 A logarithmic spiral in a natural ammonite fossil
Ammonite shells grew in a natural spiral and made a consistent, mathematically significant pattern. This special shape is known as a logarithmic spiral.
The main property of a logarithmic spiral is that the shape of the spiral is unaltered as it increases in size. Each turn is a pure geometrical progression of the last with a common ratio. This form is found in many natural phenomena, from the shape of galaxies to patterns on sunflower heads.
Staaf, Danna. Monarchs of the Sea: The Extraordinary 500-Million-Year History of Cephalopods. The Experiment, 2020.
Tsujita, Cameron J., and Gerd EG Westermann. "Were limpets or mosasaurs responsible for the perforations in the ammonite Placenticeras?." Palaeogeography, Palaeoclimatology, Palaeoecology 169.3 (2001): 245-270.
Moulton, D. E., A. Goriely, and R. Chirat. "The morpho-mechanical basis of ammonite form." Journal of theoretical biology 364 (2015): 220-230.
Lemanis, Robert, et al. "A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells." Paleobiology 41.02 (2015): 313-329.