Sapphire from the Mercaderes—Río Mayo Area, Cauca, Colombia

Sapphires from Australia

“…These features are the same as those reported at Pailin in Cambodia (Jobbins and Berrangk, 1981) and observed by the author in sapphire from Bo-Bloi, Chanthaburi, and Prae in Thailand. They also look very similar to the surface features reported on corundum from Colombia (Keller et al, 1985). Some minor water wearing is observed on the gem material recovered from alluvials, particularly from the Anakie fields.…”

Some Diagnostic Features of Russian Hydrothermal Synthetic Rubies and Sapphires

“…With an absorption maximum in the yellow and minima in the red and blue-green areas of the visible region, this spectrum reveals all the features associated with color change in a mineral (see, e.g., Hänni, 1983). In natural color-change sapphire (e.g., from Mercaderes, Colombia), this particular spectrum is caused by Fe 2+ /Ti 4+ absorption bands of blue sapphire superimposed on Cr 3+ and Fe 3+ absorption bands (figure A-2; ; see also Keller et al, 1985). In the authors' experience, natural colorchange samples from Sri Lanka and Tanzania (Umba and Tunduru-Songea areas) have almost identical spectra.…”