Assemblage of Synthetic Ruby in Calcite Matrix
The red stone’s refractive index and specific gravity were impossible to determine, and only a very small portion was visible for obtaining other information. A spectroscope was the only option, and the stone clearly showed a ruby spectrum. It also displayed strong and medium red reactions to long- and short-wave UV radiation, respectively. Microscopic examination with fiber-optic light revealed a group of round gas bubbles and tiny fractures, but curved striae were not seen. These properties indicated a flame-fusion synthetic ruby cleverly embedded in matrix to imitate natural ruby.
Raman spectroscopy identified the matrix as calcite. Close examination indicated that the cream-colored side of the stone had been drilled to make a hole for inserting the synthetic ruby. After the drilled area was sealed with a mixture of glue and calcite powder, two openings were cut to reveal the synthetic ruby inside. Under long-wave UV radiation, the drilled area showed strong greenish blue fluorescence, while the rest of the stone was inert or exhibited a light greenish blue reaction (figure 3).
These types of artificial assemblages should alert traders to exercise caution when purchasing rough stones, especially in newer, less established markets.