 The rover drove over a rock, it cracked open and revealed yellowish-green crystals that turned out to be pure sulfur never before seen on the red planet. Now scientists have to figure out what the surprise find means. Project scientist Ashwin Vasavada described it as the strangest find of the whole mission and the most unexpected, adding, I have to say there's a lot of luck involved here. Not every rock has something interesting inside. Michael Toscano, WTOP News.