Naturally irradiated diamonds usually contain areas of green or brown radiation damage on their surfaces or penetrating into the stones.

• A. Green or brown radiation damage on surfaces or penetrating into the stones
• B. Blue color on the surface
• C. No detectable damage
• D. Yellow patches only on the girdle

Answer: (A)

Natural irradiation creates color centers in diamonds, causing green or brown hues. The radiation alters the crystal lattice, producing defects that absorb light and manifest as greenish or brown areas that can sit on the surface or extend into the stone. This is why naturally irradiated diamonds often show those green or brown patches rather than a uniform color. Blue surface color isn’t the typical signature of natural irradiation, and claiming no detectable damage ignores the common green/brown zones produced by the radiation. Yellow patches restricted to the girdle don’t describe how radiation damage usually appears.