mineralogy, history, and metaphysics

Welcome to the Ammolite Fossil page. Here, you will learn everything you need to know, including mineralogy, history, metaphysics, and more!



CaCO3 + SiO2·nH2O





(Balance, Stability,

Personal Empowerment, Manifestation)

AMMOLITE, the opalized fossil remains of ammonite

Ammolite is a trade name given to the fossilized and opalized remains of certain species of ammonite. These fossils are often recovered with such great opalization that they are no longer sold as a fossil but, instead, as a gemstone, exceedingly increasing its value within the international trade markets. Most specimens of ammolite are cut and used in the art of fine jewelry making; while larger, intact displays are often sold to high end mineral collections and museums. The ammonites that form ammolite once inhabited a prehistoric, inland subtropical sea that bordered the Rocky Mountains and stretched far across the North American continent, reaching Appalachia. This vast but shallow sea is now called the Western Interior Seaway, and was home to innumerable examples of aquatic life, including various species of bony-fish, mosasaur, crocodilians, and birds. As the ammonites died, they would sink to the bottom of the sea, where they were sometimes buried within thick layers of bentonitic mud that eventually hardened and became shale. These sediments preserved the aragonite of the shells, preventing it from converting to calcite and furthering its decomposition. The complete opalization of an ammonite fossil occurs over very lengthy periods of time, with many scientific hypotheses suggesting it taking upwards of 100 million years to fully develop its opalization. First, the animal is abruptly buried and removed from the necessary elements required for decay processes to occur. In time, the shell of the animal begins its fossilization process, and its remaining organic material is replaced by influxes of aragonite and, later, hydrated silica mineralization. Opalization occurs when microscopic molecules of H2O get trapped within the surface of the now silicified fossil ammonite. When viewing an ammolite specimen, a broad range of colors can be seen on the surface of the fossil, and this is due to opals distinct refraction rate of visible light, which allows the light to penetrate the silica and become bent, obscured, and refracted within the trapped molecules of water. The water acts as a prism, and releases the light towards the eye at alternating wave-lengths, creating a rainbow of brilliant color within the fossilized surface of the long extinct creature. The most significant deposits of gem-quality ammolite have only been found in the Bearpaw Formation, which extends from Alberta to Saskatchewan in Canada, and then farther south to Montana and Utah in the United States. Small deposits of gem-grade material have been found as far south as Central Utah, but never in plentiful amounts.


Ammonites, or more formally, Ammonoids, are extinct spiral shelled cephalopods. They are closely related to living octopus, squid and cuttlefish; even more so, in fact, than they are related to the similarly shelled modern-day nautilus. Ammonites were once the most abundant form of animal life within the ancient seas. The earliest ammonites appeared during the Devonian period, roughly 400 million years ago, with the last of the species vanishing during the Cretaceous–Paleogene extinction event, roughly 66 million years ago. This extinction event is marked by the Chicxulub asteroid impact, which killed nearly three quarters of all animal and plant life on Earth. During this event, nearly all non-avian dinosaurs became extinct, with the exception of certain species of sea turtle and crocodilian. The Chicxulub asteroid is estimated to have had a diameter of roughly 9 miles wide, and its impact resulted in a nuclear winter, which fossil evidence suggests may have lasted upwards of fifteen years. During this time, photosynthesis in most plants and plankton had halted, resulting in a widespread collapse of the global food chain, creating the ensuing mass extinction. Ammonites are considered an excellent index fossil, and linking over 10,000 different species of these ancient creatures to their specific geologic time is very often possible. The smallest ammonite species had shells that measured less than an inch in size, while certain coiled species were huge in comparison, sometimes reaching more than 10 feet in diameter!


The name "ammonite" was inspired by the spiral shape of their fossilized shells, which somewhat resemble a tightly coiled rams' horn. The Roman philosopher and naturalist, Pliny the Elder, called the fossils of these animals ammonis cornua, which translated to "the horns of Amun". This is because of their connection to the Egyptian god Amun, who was typically depicted wearing rams' horns. Most often, the name of an ammonite genus ends in a conjunction of the term “ceras”, meaning horn, for this reason.


Ammonite septa tend to have characteristic bulges and indentations when viewed from the front, which distinguishes them from nautiloid septa, which are commonly found as concave, dish-shaped structures. The formation of the internal septa results in various suture patterns that are displayed across the exterior of the shell. While nearly all nautiloid shells display gently curving suture patterns, the ammonoid suture patterns are distinctly and variably folded, forming peaks that point towards the aperture, or opening, of the shell. These distinctly undulating patterns are characteristic of ammonoid fossils, and displays the growth processes of the creature’s shell during its life-span.

The internal chambers of the ammonite shell are called the phragmocone. The phragmocone contains a series of progressively larger chambers, called camerae, that are divided by thin walls called septa, (think septum in your nose). Only the largest of the chambers, called the body chamber, was occupied by the living animal. As the animal grew, it added newer and larger chambers to the open end of its coil. A very thin, living tube called a siphuncle passed through the septa, extending from the ammonite's body and through to each individual chamber. Through a process called a “hyperosmotic active transport”, the ammonite continuously filled and emptied water out of the individual chambers. This enabled the creature to control the buoyancy of its shell, enabling it to rise or descend as necessary when navigating the open water.

Much like its modern-day relatives, the squid and octopus, recent findings suggest that the ammonites use of an ink sack was its primary defense mechanism. Its other defenses against predation are found in its hardened shell elasticity, and also, its retractor muscles, which were used to pull the animal backwards and into its shell when hiding.


Metaphysically, it is said that ammonite and ammolite fossils bring its user a sense of clarity and direction, while allowing for deep meditative experiences and auric cleansing. A stone of both the Root and Third Eye chakras, its stabilizing and directive energy can help to aid with patterns of racing thoughts, and allow the mind to slow down and see the end result more clearly. Ammonite and Ammolite are said to facilitate in manifest projections, bringing goals and achievements closer to one’s attainability, while opening doors to future endeavors. It is also said that the fossils are considered stones of wealth, and can help to facilitate internal networks of communication within the work place, bringing prosperity to the business structure. Physically, these stones are said to aid the body with digestive and metabolic functions, easing symptoms of IBS and Diverticular disease. It is also said that ammonite and ammolite fossils can aid with inner ear function, as well as relieve pain caused from tinnitus.