Tourmaline Buying and the Four Cs
The IGS tourmaline value listing has price guidelines for paraíba?tourmalines, indicolite, rubellite, chrome tourmalines, and other colors of faceted stones, as well as cat’s eye and non-phenomenal cabochons.
Tourmalines come in all the colors of the rainbow. When buying tourmaline of any color, view it under several different types of lighting, as most gems will exhibit some alteration in color or decreased saturation in incandescent light.
In tourmalines, blue and blue-green hues arise from iron or copper in the crystal structure. While rare, blue hues are also the most popular color of this gemstone.
Indicolite is the gemological name for blue tourmalines. Generally, this term refers to tourmalines colored by iron. Indicolites can be greyish blue, blue, or blue-green. The most costly gems exhibit medium tones and saturated color. Since indicolites commonly receive heat and radiation treatments, ask about treatments before purchasing.
If you’re interested in indicolites, read the indicolite buying guide.
In 1989, a new variety of tourmaline came out of Brazil. This material, called “paraíba tourmaline” for the Brazilian state of Paraíba, displays an electric blue to blue-green hue due to the presence of copper. Before the…