Ever wonder how Earth scientists examine rocks? We cut them up and throw them under a microscope ... and then everything ...

Minerals are typically formed when molten rock, or magma, cools, or by separating out of mineral-rich water, such as that in underground caverns. In general, mineral particles are small ...

When that mineral forms and the rock cools enough that argon can no longer escape, the "radiometric clock" starts. Over time, the radioactive isotope of potassium decays slowly into stable argon ...

A new plan is forthcoming by the end of the year. Original article source: Cool rocks: NASA's Mars rover shows off its rock core collection ...