Aging nuclear infrastructures prompt the need for accurately characterizing radiation damage in various structural components of a nuclear power plant, including concrete. The most significant damage, from neutron radiation, occurs in siliceous aggregates and thus granite is a target rock for understanding radiation damage.
Typical granite contains a complex mixture of minerals, and their identification is not straightforward. Previous approaches for obtaining phase compositions have relied on methods like optical petrography and electron microscopy, which often require laborious sample preparation procedures, in addition to stochiometric assumptions, which are ineffective in detecting polymorphs of the same mineral. In this study, we formulate a custom confocal Raman imaging protocol which allows direct mapping of mineral polymorphs on surfaces of unprepared samples, ensuing in high-fidelity and high-resolution mineral phase maps. Specifically, we demonstrate an accurate analytical methodology for mineral identification that can be applied to any multiphase system that is heterogenous.