Veins in 'Sheepbed' outcrop

A rock outcrop at a location nicknamed "Sheepbed" shows well-defined, whitish veins that NASA believes to be calcium sulfate.

On Earth, these veins form when water flows through fractures in rock, depositing minerals along the sides of the fracture and eventually forming a vein. These veins are Curiosity's first look at minerals that formed within water that percolated within a subsurface environment.