Gemological, chemical, and spectroscopic properties are presented for the first known transparent faceted grandidierite. This jewelry-quality 0.29 ct stone was fashioned from rough reportedly found in the Kolonne area of Sri Lanka. The greenish blue borosilicate has refractive indices of 1.583 to 1.622, which correlate to a low iron content of 1.71 wt.% FeO and readily separate it from the gem material closest in properties, lazulite.
Gemological, chemical, and spectroscopic properties are presented for the first known transparent faceted grandidierite. This jewelry-quality 0.29 ct stone was fashioned from rough reportedly found in the Kolonne area of Sri Lanka. The greenish blue borosilicate has refractive indices of 1.583 to 1.622, which correlate to a low iron content of 1.71 wt.% FeO and readily separate it from the gem material closest in properties, lazulite.