Irradiation of a type 1 diamond creates what bodycolors?

• A. Blue only.
• B. Green only.
• C. Yellow to red.
• D. Blue to green bodycolor depending on starting material.

Answer: (D)

Irradiation creates vacancy-related color centers in the diamond’s lattice. In type 1 diamonds, which contain nitrogen as impurities, these vacancies interact with nitrogen during subsequent treatment to form centers that absorb light in ways that produce color. The exact hue you get isn’t fixed; it depends on how much nitrogen is present and in what form, so the resulting bodycolor can range from blue to green. That variability is why blue to green is the correct general outcome for irradiation of type 1 diamonds.

The other possibilities are too restrictive or incorrect for this scenario. A single blue or a single green color doesn’t capture the material-dependent range, and yellow to red isn’t the typical product of irradiation in type 1 diamonds.