Characterization of ores and different mineral solids is essential at all stages of critical mineral production ranging from exploration, mining, mineral processing, and metallurgical extraction. The different mineral solids that need characterization include bulk ores, floatation concentrates, different mineral fractions produced during mineral processing, tailings, and gangue minerals. Chemical and mineralogical analysis improves the profitability of critical mineral production by enabling plant design, process control, process optimization, better utilization, and management of the different mineral fractions. This chapter introduces the subject of chemical and mineralogical analysis and the common characterization techniques that are routinely used for it including optical mineralogy, mineral liberation analysis, electron probe microanalysis and laser-induced breakdown spectroscopy. The chapter concludes with a brief on the role of additive manufacturing in the characterization of critical minerals.