A petrologist uses microscopes and chemical tests to determine the nature of rocks and minerals. Microscope examination of a rock specimen mounted on a "thin section" slide is the principal technique used to identify the rock specimen. Further study can determine the components and features of the rock along with its composition, how it was formed and the geological setting of the rock.
Stained slices, hand specimens, or loose grains of rocks and minerals can be examined with an ordinary incident light stereo microscope like our EMZ-13TR Stereo Microscope with PKL-2 Stand. But thin sections are examined with a transmitted light polarizing microscope like Meiji's ML9000 or MT9000 Series.