Characteristics of Channel-Water in Blue-Green Beryl and Its Influence on Colour

Abstract

This study reports the characteristics of water in channels of blue-green beryl and its effect on color. An industrial camera was used to measure color in the CIELAB color space. X-ray fluorescence (XRF), X-ray diffraction (XRD), infrared spectroscopy (IR), ultraviolet-visible (UV–vis) spectroscopy, and silicate rock chemical analysis method were used for analysis. The peaks at 5105 cm−1 and 5269 cm−1 were the combination tone of type II water, which were negatively correlated with b*, and positively correlated with the peak area at 3162 cm−1 (Na–H) and cell parameter a0. The peaks at 7097 cm−1 and 7142 cm−1 were related to the metal ions types in the channels. Part of the water in the channel combined with Fe3+ to form [Fe2(OH)4]2+ and cause a yellow tone, and when the yellow tone combined with the blue tone caused by Fe2+, the beryl has a blue-green colour.