synthetic beryl, emerald, gems

Gübelin examines a series of “Emerita” stones produced by Johann Lechleitner, consisting of natural beryl cores coated with a synthetic emerald overgrowth. The specimens demonstrate that even differently colored beryls, including blue aquamarine and yellow heliodor, can acquire essentially the same emerald-green appearance when covered by a sufficiently thick synthetic layer. Conventional physical constants may fail to distinguish these composite stones from natural emerald, making microscopic examination particularly important. Gübelin describes the boundary between the natural beryl core and synthetic emerald mantle and the characteristic inclusions and growth features within the coating, illustrating them with photomicrographs. The study emphasizes the gemological identification problems created by synthetic emerald overgrowth and demonstrates that recognition depends chiefly on careful observation of the coating and its microscopic structural features.