Patina
Also: mineral staining, coloration
The mineral coloration and surface character a fossil takes on during burial. Iron, manganese, and phosphate produce distinctive hues; natural, embedded patina is one sign a fossil is genuine.
Patina is the color and surface quality a fossil acquires over millions of years underground. As mineral-rich groundwater seeps through the buried tooth, iron, manganese, phosphate, and carbon settle into its pores — iron toward reds and browns, manganese and iron sulfides toward blacks and grays, and trace minerals such as glauconite toward the rarer blues and greens — giving each specimen its own palette. No two are alike.
Patina and authenticity
Genuine patina looks embedded in the enamel and root rather than painted on, and a tooth's color often shifts as it dries, because air-filled pores scatter light differently than water-filled ones do. Artificial dye on a replica tends to look too uniform or rubs off at the edges. Mismatched patina across a single tooth can also reveal a composite.
What patina says about origin
Because color tracks the minerals in the burial sediment, patina is a clue to a tooth's formation and locality — part of why we describe color honestly rather than enhancing it. Our guide on cleaning and displaying fossils explains how to preserve patina rather than scrub it away.
Color is character, not quality by itself — a darker tooth is not automatically better, just differently mineralized.