Learn about Pyritized Fossils

The Beauty of Geochemistry

Pyrite—often called “Fool’s Gold”—is an iron sulfide mineral that, under rare geochemical conditions, can coat or even replace prehistoric organisms, transforming them into luminous, gold-toned fossils. These pyritized fossils are among nature’s most striking creations, uniting chemistry, time, and artistry in a single form.

Beyond their beauty, they reveal clues about ancient worlds. Research shows that pyritization occurred when creatures such as trilobites, ammonites, and plants were rapidly buried in ocean sediments poor in organic material and oxygen. In these anaerobic environments, decay slowed dramatically, allowing unique chemical reactions to unfold before the remains disintegrated.

As sulfate-reducing bacteria thrived in these oxygen-starved waters, they converted sulfate ions into sulfides, which then reacted with dissolved iron to form pyrite. This mineral gradually replaced or coated soft tissues and skeletal structures, preserving extraordinary anatomical detail—sometimes down to the finest filaments or shell textures.

The result is both scientific and sculptural: organic life turned to metal, shimmering with the golden glow of deep time.

You can view select pyritized ammonites our ammonite collection. 
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