Curiosity Accidentally Crushed a Rock of Pure Sulfur

The Curiosity rover drove over a rock and split it open. Inside were crystals of pure sulfur — the first ever found on Mars.

It happened on May 30, 2024. The rover rolled across the rock and crushed it under its weight. A few days later, Curiosity photographed the fragments with a camera on the end of its robotic arm. The image shows pieces of sulfur crystals.

The find matters because this is pure, elemental sulfur. Earlier missions on Mars had found only sulfur compounds bound to other elements, not the element itself in free form.

A recent paper in Science offers an explanation for the crystals' origin. The authors suggest the sulfur formed about 3 billion years ago. Magma deep below the surface released fluids or gases that deposited the sulfur on top.

This remains a hypothesis, not a settled conclusion. But the presence of pure sulfur adds detail to the picture of the planet's geological past — a time when active processes were still at work beneath the Martian surface.