Which colors indicate radiation damage in natural diamonds?

• A. Green or brown radiation damage
• B. Blue coloration
• C. Pink hue
• D. Yellow tint

Answer: (A)

Natural irradiation from radioactive materials in the Earth can create color centers in the diamond’s crystal lattice, altering which wavelengths are absorbed and giving the stone a green appearance. Brown can also result from radiation damage, especially when defects darken the lattice or after irradiation is followed by heating. These colors reflect the specific way radiation modifies the lattice, whereas blue, pink, or yellow tones arise from different causes: blue is typically from boron impurities, pink from unique lattice defects and deformations, and yellow from nitrogen coloring. So green or brown shades are the best indicators of radiation damage in natural diamonds.