What color do you get when you irradiate and anneal a type Ib diamond?

• A. Blue bodycolor.
• B. Yellow bodycolor.
• C. Brown bodycolor.
• D. Pink bodycolor.

Answer: (D)

In type Ib diamonds, nitrogen appears in isolated atoms throughout the lattice, giving a natural yellow color. When such a diamond is irradiated, vacancies are created in the crystal. Heating after irradiation allows those vacancies to move and interact with the nitrogen atoms, forming specific defect centers. In nitrogen-rich (type Ib) material, this combination of vacancies and nitrogen-related centers changes how the crystal absorbs light in a way that produces a pink hue. So irradiation followed by annealing typically yields pink diamonds in this material type, a result that differs from how other impurities or treatments color other diamond types. Natural pinks, by contrast, arise from different lattice distortions, not this defect-chemistry pathway.