For example, the UV test—a common at-home method—calls for you to place the diamond under a UV light. If the gemstone gives off a blue glow, it's thought to be real. However, Zhang points out ...

the "diamond" doesn't have the proper light dispersion properties that real diamonds possess. About 30% of diamonds will glow blue under ultraviolet (UV) lights (such as black lights). On the ...

After years of disavowing the authenticity of man-made diamonds grown in a laboratory, De Beers has suddenly seen the light and responded ... on colored pink and blue stones to compliment the ...