There are many observational technologies that can be used to supplement or quantify optical petrographic observations. Some apply directly to light microscopy (staining, for example), some are done with light microscopes but require specialized additional equipment (fluid inclusion geothermometry, some forms of cathodoluminescence and fluorescence microscopy), and others require completely different and typically more expensive instrumentation (SEM/TEM, microprobe/ion probe, X-ray computed tomography and many others). Examples of output from some of the most common and best established of these techniques have already been shown and referenced throughout this book (e.g., staining, fluorescence, SEM and backscattered electron imaging) and so will not be further illustrated here, although useful summary and case-study references are provided at the close of this chapter. One well established technique, cathodoluminescence, has undergone new instrumentation developments, including diversification from light microscopes to scanning electron microscopes, and so it will be featured in this chapter along with two other relatively new and promising imaging and analysis technologies, including X-ray computed tomography, grouped here under the term “digital rock physics”. These technologies are evolving rapidly and the descriptions in this chapter will soon be superceded by new developments. Nonetheless, they should serve to show readers to the potential of such technologies to enhance petrographic investigations.