Figure 1. This 239.25 ct topaz crystal hosts some interesting inclusions of ferrocolumbite. Photo by Diego Sanchez. The author recently acquired a 239.25 ct transparent well-formed topaz crystal from ...
Natural-color saltwater cultured pearls from Pinctada margaritifera were studied by diffuse reflectance UV-Vis-NIR spectroscopy to identify the absorption features associated with their various colors ...