Back in January, the Mars Curiosity rover did what it was built to do: It plowed over some rock. On this particular day, however, one of the rocks the rover roved over broke apart -- revealing, in pictures beamed back to Earth, a shiny-white interior that stands in sharp relief against the dusty-red Martian landscape. "This is one of the brightest and whitest things we've seen with the Mastcam [Curiosity's camera] at the Gale Crater site," Caltech's Melissa Rice said of the object. 

Scientists have since been analyzing information about the mystery rock -- nicknamed, awesomely, "Tintina" -- and today, at the annual Lunar and Planetary Science Conference (LPSC) in Texas, they've released their findings.

And those findings, like so many of the things we learn about Mars with the help of our little robotic liaison, represent both "discovery" and "mystery." We know, for example, that the chalky-white rock is roughly 1.2 inches by 1.6 inches -- the size, basically, of a large marble. The images of Tintina's seam would also seem to indicate the presence of hydrated minerals -- the kind so familiar to us here on Earth. Which might also indicate the presence (or, the erstwhile presence) of water. And which offers yet more evidence that the area Curiosity is roving -- Yellowknife Bay -- was once home to the life-friendly liquid.

As Rice explained to the BBC: "What Mastcam is seeing is water that is bound in the mineral structure of the rocks. This water is left over from a previous wet era and is now trapped and preserved in these hydrated minerals."

The Tintina announcement comes hot on the heels of one of Curiosity's biggest findings: that Mars boasts environmental conditions that could once have supported life as we know it. And Curiosity has observed, as well, what scientists believe to be the remains of an ancient riverbed near its landing site at the Gale Crater. "The picture that seems to be emerging," the BBC put it in a report from the LPSC, "is one where sediments were transported downhill from the eroding crater rim into a network of streams that then flowed into a lake environment represented by the mudstone drilled by Curiosity." And it's a picture made a little clearer by Curiosity's serendipitous excavation. Mars, site of an ancient Slip 'n Slide! Just one more piece of information about the Red Planet, brought to you by a white rock.