Rare, Natural Bluish-Green Grandidierite. Perfectly Suited as an investment & Collector's Gem Gem Details: ICA Certificate No. TH25G117437 Species - Grandidierite Weight - 4.18 Carats Color - Bluish-Green Shape - Oval Cutting Style: Crown - Brilliant Cut Cutting Style: Pavilion - Modified Brilliant Cut Transparency- Transparent with beautiful Luster Measurements - 10.90 x 9.15 x 6.17mm Comments- None About Rarity and Origin Grandidierite is an extremely rare greenish blue orthorhombic borosilicate with the formula (Mg,Fe)Al3(BO3)(SiO4)O2. It is the magnesium end member in a solid-solution series where the stoichiometric concentrations of Mg and Fe will vary and determine the ultimate nomenclature of the mineral. Ominelite is the iron end member. The structure of grandidierite is made up of BO3 triangles; SiO4 tetrahedra; distorted AlO5, MgO5, and FeO5 trigonal bipyramids; and AlO6 octahedra. Grandidierite characteristically forms in translu Shipping will be via FedEx and DHL with full insurance. Customs and Import fees are sole responsibility of the buyer.