Glowing spider fossils may exist thanks to tiny algae’s goo 

A sulfur-rich diatom secretion coated the arachnids, helping preserve them, a study suggests

a fossil spider, with an inset showing the fossil in ultraviolet light that revealed a substance possibly produced by diatoms

This fossilized spider is part of a trove from France, dating to about 22 million years ago. Using ultraviolet illumination (inset), scientists found that the fossil was coated in a sulfur-rich substance possibly produced by ancient diatoms. That substance may have been key to the fossil’s preservation.

A. Olcott

The secret ingredient for fossil preservation at a famous French site wouldn’t be found in a Julia Child cookbook.