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Why Are Sharks Teeth Black

Why Are Sharks Teeth Black

Sharks are formidable ocean predators armed with rows of razor-sharp teeth. But while living sharks have whitish teeth, fossilized shark teeth are almost always black. So why do these particular shark teeth turn black?

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Shark Tooth Composition

Tooth LayerComposition
EnamelHydroxyapatite crystals
DentineHydroxyapatite crystals, collagen fibers

Shark teeth contain enamel and dentine like other animals. But additional minerals are absorbed during fossilization.

How Fossilization Transforms Color

Shark teeth can become fossilized when they fall out and become buried in sediment on the seafloor. Over long periods, the sediment:

  • Pushes minerals like phosphate into the tooth, replacing organic material
  • Crystallizes the minerals, turning teeth black through a process called permineralization
  • Applies pressure that accelerates the color change

This blackening fossilization process takes at least 10,000 years. Most fossilized shark teeth are hundreds of thousands to millions of years old.

Why Finding Black Teeth Is Common

  • Sharks shed over 40,000 teeth in a lifetime
  • Mineral-rich sediments like phosphate are excellent for the preservation
  • Coastal areas with fossil shark teeth have ideal conditions


Next time you find a black shark tooth, you can be sure it has been transformed by many years of fossilization! The black color is a testament to the tooth’s ancient origin.

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Steve Momot

Steve is an accomplished professional photographer and marketer who specializes in the Fishing, Yacht, and Boating industry. With a strong presence as an influencer and marketing expert in the Marine Industry, he has made a significant impact in the field. Additionally, Steve is the original creator and co-founder of Sportfishtrader. Prior to his career as a marine photographer, he gained extensive experience as a licensed boat and car dealer in South Florida.

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