Fluorescence microscopy can recognize depositional facies and delineate diagenetic fabrics and porosity relationships in certain highly dolomitized or recrystallized limestones previously uninterpretable using standard petrographic techniques. This tool has other valuable applications in the study of carbonate rocks. These other applications include differentiating carbonate cements from neomorphic spar, enhancing depositional and diagenetic fabrics, rapidly evaluating mineralogical stabilization and recrystallization in Holocene and Pleistocene deposits and improving delineation of porosity and pore geometries in sedimentary rocks. Fluorescence microscopy is a rapid, easily used and nondestructive technique that can be applied to unpolished thin sections or rock slabs. By itself, or in conjunction with other petrographic and geochemical tools, it has the potential to expand our understanding of carbonate diagenetic processes and products, in particular dolomitization and neomorphism, and carbonate porosity evolution. We strongly encourage routine usage of fluorescence microscopy in future carbonate petrographic studies.