A natural phosphorescent calcite fossil clam (Mercenaria permagna) dating to the Early Pleistocene, approximately 2 million years old.

Over millions of years, this ancient clam shell became naturally hollow and was lined with honey-golden dogtooth calcite crystals. Under both shortwave and longwave ultraviolet light, the calcite fluoresces a bright green and continues glowing for several seconds after the UV source is removed—a rare property known as phosphorescence.

The exterior preserves much of the original fossil shell, while the interior reveals sparkling calcite crystals surrounded by cream-colored shell material. The reverse side retains natural fossil matrix with additional marine fossils preserved in the rock, adding another layer of paleontological interest.

A video demonstrating the phosphorescent afterglow is included with this listing.

Details

• Fossil: Mercenaria permagna (fossil clam)

• Age: Early Pleistocene (~2 million years old)

• Interior: Natural dogtooth calcite crystals

• Fluorescence: Bright green under shortwave and longwave UV

• Phosphorescence: Continues glowing briefly after the UV light is removed

• Weight: 172 g

• Size: Approximately 3.8 inches

• Natural collector specimen

• One-of-a-kind display piece

You will receive the exact specimen pictured.