corundum, synthetic corundum.7, Ramaura, flux, gems

Bosshart presents the first gemological investigation of the newly introduced Ramaura synthetic ruby. Seven specimens ranging from intense red to pale violet-red were examined. Particular attention is given to microscopic inclusions and ultraviolet-visible absorption spectra, with significant differences observed between the strongly colored and paler material. The intense red specimens contained substantially more inclusions, while spectrophotometry revealed two distinct types of absorption behavior corresponding to the different color groups. Some Ramaura rubies showed properties sufficiently similar to natural ruby to make identification difficult, emphasizing the importance of microscopic examination and spectrophotometry in distinguishing this new synthetic material.