Analyses done at the Netherlands Gemmological
Labora tory included standard gemological testing and
UV-Vis-NIR, FTIR, and Raman spectroscopy. A Rayner
refractometer (yttrium aluminum garnet prism) with
a near sodium–equivalent light source was used to
measure refractive index and birefringence, specific
gravity was determined hydrostatically, a calcite dichroscope
revealed pleochroic colors, long- and short-wave
UV lamps were used in a darkened room to observe
fluorescence, and absorption spectra were visualized
with a System Eickhorst M9 spectroscope with a builtin
light source. Internal features were observed with a
standard gemological microscope and a Nikon Eclipse
E600 POL polarizing microscope.