corundum, synthetic corundum.7, Ramaura, synthetic garnet, gems

Gübelin describes two recently introduced artificial gem materials: Ramaura flux-grown synthetic ruby and yttrium gallium aluminate (YAG), the latter marketed as a green imitation of tsavorite garnet. The first portion discusses the manufacture and gemological properties of Ramaura ruby and emphasizes microscopic features useful for separating it from natural ruby, particularly characteristic flux residues and growth-related inclusions. The later installments treat yttrium gallium aluminate, describing its physical and optical properties and characteristic inclusions. The green material has a high refractive index and specific gravity and contains distinctive reddish-brown flux inclusions and wispy veil-like features. The series illustrates the importance of inclusion microscopy in recognizing artificial gem materials whose appearance may closely resemble natural gemstones. Contemporary abstracts confirm that the second installment concentrates on characteristic inclusions and the third on the physical and optical properties and inclusions of yttrium gallium aluminate.