In a darkened room at the American Museum of Natural History in New York, a wall of unassuming stone stretches nearly to the ceiling. At first glance, it looks like a slab destined for a kitchen island or countertop, with black, white, and pink speckles mixing in bands of minerals that stretch far above my head. But then the display light flicks from white to black, and the 10-ton rock glows neon orange and green.

“You cannot help but drop your jaw," says George Harlow, the curator of the museum's newly renovated Mignone Halls of Gems and Minerals, where the rock stands.

The stunning vibrancy betrays the minerals' uniqueness: They formed on the bottom of a now-vanished ocean