As per my information, Jewels will shine just within the sight of a light source. Precious stones get their brightness from three things: reflection, refraction, and scattering. A portion of the precious stone that has brilliance will shine without light when presented to UV lights. Precious stones are faceted to be reflectors of light. Every feature reflects light and that is the thing that gives a precious stone its sparkle. A very much cut precious stone will truly shimmer in the light. Reflection is the light that hits the diamond and is promptly skipped back up, giving it a momentary sparkle.