Conclave 2026

Fluorescence remains one of the most discussed – and often misunderstood – properties in diamond grading. While strong market opinions persist, the scientific and visual realities are more nuanced. In this 45-minute presentation, Dr. Mike Breeding examines fluorescence through three lenses: history, research, and observable appearance. Drawing on recent advances in imaging and measurement technology, a GIA research team has quantitatively characterized the relationship between blue fluorescence intensity and its effects on table-down color, face-up color, brightness, and transparency under controlled illumination. The session will also address the distinction between fluorescence-related contrast effects and transparency reduction caused by structural light scattering. By separating perception from measurable optical behavior, this research aims to reduce long-standing confusion and provide a scientific foundation for informed discussion of diamond fluorescence.