A rock on Mars spilled a surprising ... pretty big that we're not aware of. Sulfur, it's important to understand, is an ...

Nasa used the robot's instruments to analyse the rock, receiving data that indicated it was pure sulphur. Scientists were "stunned", said Nasa when it revealed the discovery last week.

When making steel, it reacts with sulfur and helps to increase the ... abundant element in the earth's crust and can be found in rocks, sand and clay. It acts as a deoxidizer in steel production.

A rock very similar to the one broken by Curiosity, photographed nine days after the sulfur discovery ... taken up in the form of sulfates, and used to make two of the essential amino acids ...