Why does one of the diamonds that surround the Hope Diamond shine blue when exposed to UV light?

I was looking up pictures of the Hope Diamond and one of the pictures showed it when it was placed under a UV light. As we all know it turns an eerie red when exposed to UV light, but the surrounding diamonds can't really be seen except for one which shines a light and bright blue. Anybody have any idea what type of stone it is?|||Tia,





The one that fluoresces blue is also a diamond. The fluorescence of diamonds depends on impurities within the crystal structure of the diamond (tiny amounts of elements besides carbon). The Hope Diamond itself is now thought to fluoresce because of a boron impurity, according to recent research. The fluorescence of the blue one is just due to a slightly different chemical composition than the other diamonds that surround the Hope.|||Diamonds often fluoresce blue of varying brightness to UV light. But, other diamonds don't glow much at all. When they picked the diamonds to surround the Hope, as in the photo below, they used one that has strong blue fluorescence.