Just saying that Spirit and Opportunity have cameras and some fancy radio equipment really doesn't cut it. At 384 pounds (170 kilograms) each -- and a total of $850 million to build -- you better believe the equipment is not just your trusty MacBook, superglued to an AM/FM radio.
First of all, a panoramic camera is mounted on each rover to provide a larger geologic context. Located on the mast about 5 feet (1.5 meters) off the ground, the camera doesn't just snap color images but carries 14 different filters that can identify rock and soil targets for closer looks.
A miniature thermal emission spectrometer identifies minerals at the site with a little help from infrared wavelengths. It's used to find distinctive patterns that could show water movement. On the rover arm is a Moessbauer Spectrometer, which is placed directly on samples to find iron-bearing minerals, another tool to help determine how water has affected the soil and rock.
To determine the composition of rocks, an Alpha Particle X-ray Spectrometer is used -- the same kind found in geology labs, which helps scientists determine origins and changes in the samples. The microscopic imaging tool can carefully investigate rock formation and variations.