During the past two-and-a-half years of traversing the central part of Gusev Crater, NASA’s Mars Exploration Rover Spirit has analyzed the brushed and ground-into surfaces of multiple rocks using the ...

A little knowledge of rocks and minerals will help you identify everything from jewelry to fossils. While reading this article may not turn you into a geologist, it should give you the basic ...

VOLUMES 3 and 4 of this work complete what must be the most compendious hand book of petrography ever issued. In the first volume Johannsen gave an admirably illustrated account of rock textures and ...