Even if my stone is clean, it misses the brilliance and clarity I thought it had.
Our answer on this question:
In order to get the full brilliance and sparkle from your natural stone, it is important to get the right light sources above it.
Like on rainy, cloudy days, light sources like incandescent light bulbs, fluorescent lamps, and compact florescent lamps, create a multidirectional light with very low local intensity. Any other light source with a wide angle output has to some extent the same problem.
To create the beautiful light of a sunny day, we recommend installing narrow angle (less than 20°, often just called spot) halogen or even better, new generation high power LED (300lm and up, 2800 – 3200 K). Not only your stone will look prettier, the whole room will look more interesting and appealing.