What is the most reliable and precise determination of diamond type?

• A. Visual inspection
• B. X-ray diffraction
• C. Spectroscopy
• D. Infrared analysis

Answer: (C)

Diamond type is defined by impurity content and how those impurities are arranged in the lattice. Spectroscopy provides the most reliable and precise way to uncover that information because it analyzes how the diamond interacts with light across different wavelengths to reveal exactly what impurities are present (such as nitrogen and boron) and how they are configured (isolated atoms, pairs, or aggregates). This level of chemical and structural detail is what lets you distinguish Type Ia from Ib and Type IIa from IIb with confidence. Visual inspection cannot reveal impurity content, X-ray diffraction shows only crystal structure and is not sensitive to trace impurities, and infrared analysis is a specific method within spectroscopy. Overall, spectroscopy gives the broad and definitive diagnostic needed to determine diamond type.