Which color get?
When exposed to short-wave UV light (also known as UV-C light) with a wavelength of around 254 nanometers, CVD diamonds typically exhibit a blue-green fluorescence. This fluorescence is caused by trace amounts of boron or nitrogen impurities in the diamond crystal lattice, which absorb energy from the UV light and re-emit it as visible light in the blue-green part of the spectrum.
It's important to note that not all CVD diamonds will exhibit fluorescence under short-wave UV light, and the intensity and color of the fluorescence can vary depending on the diamond's composition and other factors. Additionally, fluorescence alone does not necessarily indicate the quality or value of a diamond, and other factors such as size, color, clarity, and cut quality are also important in determining a diamond's value.