The ImaGem system is an automated optical instrument developed by ImaGem Inc. in the early 2000s for measuring diamond cut, light performance, colour and clarity through machine vision. The device images a diamond from multiple angles, captures the way it returns light under controlled illumination, and produces a quantitative report intended to remove human variability from the grading process.

ImaGem's stated approach combines three measurements: light behaviour through the crown and pavilion to characterise brilliance, fire and scintillation; geometric proportions including table, depth, crown and pavilion angles; and clarity assessment through automated detection of inclusions. The system was promoted as a route to consistent grading at scale and was taken up by some retail and laboratory operations, although it never displaced GIA, IGI, AGS, HRD or GCAL reports as the primary trade reference.

The wider context for ImaGem is the broader move from the late 1990s onward toward instrumented diamond grading, which has produced devices including AGS Performance Grading instruments, Sarine's optical and inclusion-mapping systems, and the various brilliance-imaging cameras now standard in retail. ImaGem's contribution belongs in that lineage rather than as a singular product.