What is diffusion treatment in diamonds and what color effect does it produce?

• A. A laser polishing process that changes color
• B. A diffusion process at high temperature where elements diffuse into the lattice to alter color
• C. A surface coating applied to change color
• D. Natural color zoning caused by impurities

Answer: (B)

Diffusion treatment involves heating diamonds at high temperature so that selected elements diffuse into the crystal lattice. As these elements migrate into the lattice, they create new color centers or modify how light is absorbed, producing a color change that is intrinsic to the stone. The most familiar result is blue diamonds formed by diffusing beryllium into the lattice, though other elements can yield different hues. Because the color is introduced inside the diamond rather than on the surface, the change is generally permanent. This is different from a surface coating or a laser color alteration, and it’s not natural color zoning caused by impurities.