Meagan Harris is the News Director for First Coast News. "Running in Heels" is a blog where Harris shares her perspective and stories as a working mom in the media.

I’ve discovered that you’re either the kind of person that can spot a shark’s tooth in the sand or you’re not.

My daughter and I fall in the ‘we can’t spot them’ category.

For years, we’ve walked the line of shells at Mickler’s Beach searching for those elusive shiny black triangles. We’ve found plenty of broken pieces of shells, crab legs and trash but never a shark’s tooth until this weekend. And if I’m being totally honest, we didn’t exactly find these either.

We did spend a lot of time searching before finally asking another beachgoer if they had spotted one. The man pulled out a Ziploc bag filled with a dozen or so. Clearly, he has an eye for it! His advice—look for the color black in the sand. Sure. It’s easy. Right?

Eventually he took pity on my sweet 6-year-old and let her pick out a tooth. Her toothless smile beamed in the sun. “Finally, a shark’s tooth!” she says. She then held it up to the open gap in her own mouth and wondered how it would look. A barrage of questions followed.

“How do sharks pull out their teeth if they don’t have hands?” she asks. And of course, “Why are their teeth black?”

Aw, I love the mind of a curious child.

I went to shark expert Dr. Jim Gelsleichter, Director of the UNF Coastal and Marine Biology Flagship Program, for answers. There are plenty of shark’s teeth that wash up on the shore. Dr. Gelsleichter says the reason the teeth you find on the beach are black is “shark’s teeth fossilize over time when they are buried.”

He went on to explain it “turns black because the calcium in the teeth is replaced by minerals from the surrounding environment."

Sharks are cartilaginous fish. That means their skeleton is cartilage. When a shark dies, its body doesn’t fossilize but its teeth do. And guess what? It is possible to identify the kind of shark by the tooth. Dr. Gelsleichter says to “keep in mind that shark teeth vary in morphology based on their location in the jaw. Therefore, identification may not be as straightforward as we sometimes make it out to be.”

So, where is the best spot to find shark’s teeth? Dr. Gesleichter says, Mickler’s Beach. It’s not a given though. That’s where my kiddo and I have been searching for years!

In the end, it’s not the shark’s tooth that’s the treasure. It’s the memories. A little girl, after all, doesn’t stay six forever.