|Top Image - Normal lights on black plastic.
Middle Image - Captured through the LED ring light. Far more facets showing reflections, and multi-colored reflections visible in the cut CZ.
Bottom Image - gemstones sitting in the circular L.E.D. (light emitting diode) microscope light.
White L.E.D.s produce bright, small sources of light that work really well with gemstones. They work exceptionally well with high refractive index and high dispersion stones like diamond, zircon, and cubic zirconia.
White L.E.D. ring lights are available from (lets all sing it together now) E-bay at fairly reasonable prices. The one I purchased has a rheostat control that lets me change the total output of the light.
It was designed to fit around the bottom ocular of a stereo microscope, but the ring also slides nicely around my Nikon macro lens, and I use it there now more often than on the scope
Notice in the upper two images the increased color of the reflections in the L.E.D. image. The highlights show flashes of blue and yellow that fail to materialize in the top (5000¬†K) lighted image.
For a less expensive experience, try a small white L.E.D. flashlight as a front high-lighter on your gemstones. Lights with as few as 8 or so L.E.D.s work on single stones. Just hand hold it as you shot the picture.