<http://schema.org/articleBody>
"  The first rock that Curiosity&amp;#039;s science team chose for contact science on Mars has turned out to be an especially interesting one, researchers said during a press conference today. The big rover arrived at &amp;quot;Jake Matijevic,&amp;quot; a triangular hunk one foot wide, on September 20. Curiosity&amp;#039;s intention was to study the chemistry of this igneous rock for more clues about Mars&amp;#039;s history. Though sedimentary rocks are the best for estimating habitability, igneous rocks like Jake are &amp;quot;better behaved,&amp;quot; according to Roger Weins of the Los Alamos National Laboratory, principal investigator for Curiosity&amp;#039;s Chemistry and Camera (ChemCam).  Edward Stolper, provost of Caltech, uses his example to explain why these rocks are so interesting: Igneous rocks form when rock at the core of a planet melts and, with its newfound lesser density, travels toward the surface. As it travels and passes through cooler rocks, the motlen rock also cools. Water and some minerals crystallize out, concentrating what remains. The leftovers turned into what Jake is today. This process is basically the same way colonial Americans made apple jack liquor, Stopler says. These early innovators would set barrels of hard apple cider outside to freeze in the winter. Repeated freezing crystallizes out water, leaving more concentrated alcohol\u2014and eventually liquor. In this metaphor, Jake is the liquor. So what does Jake tell scientists about Mars? &amp;quot;We used the ChemCam to analyze 14 points on Jake, and found a mineral composition we haven&amp;#039;t seen before on Mars,&amp;quot; Weins says. Jake is made mostly of silicon, aluminum, sodium, and potassium, [which is] characteristic of feldspar minerals. Levels of magnesium, iron and nickel are uncharacteristically low, suggesting that these crystallized out during the cooling process. Stopler says, &amp;quot;It&amp;#039;s a type of rock that is uncommon, but well studied, on Earth.&amp;quot; He&amp;#039;s still hesitant to extrapolate from a single rock about the watery history of Mars, but for this kind of rock to form on our home planet requires high pressures and a wet environment. Stopler, however, hedges the excitement by noting that alkalic igneous rocks can form other ways. &amp;quot;This gives us a broader view of the Martian interior than we previously had,&amp;quot; says Stolper. Image: This image shows where NASA&amp;#039;s Curiosity rover aimed two different instruments to study a rock known as &amp;quot;Jake Matijevic.&amp;quot; The red dots are where the Chemistry and Camera (ChemCam) instrument zapped it with its laser on Sept. 21, 2012, and Sept. 24, 2012, which were the 45th and 48th sol, or Martian day of operations. The circular black and white images were taken by ChemCam to look for the pits produced by the laser. The purple circles indicate where the Alpha Particle X-ray Spectrometer trained its view. Credit: NASA/JPL "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/space/moon-mars/a8146/what-martian-rocks-and-applejack-liquor-have-in-common-13612878/>