Blue Tourmaline - Brazil: Tourmalines are the most colourful gemstone group. A tourmaline which is pure blue is a rare thing indeed. Mostly, the blue colour has a more or less noticeable touch of green. These rare blue gemstones originate mostly in Brazil. They are also found today in the gemstone mines of Namibia, Afghanistan, and Pakistan and, recently, also in those of Nigeria.
A tourmaline and diamond ring, Nardi centering an elongated marquise-cut greenish blue tourmaline, weighing 6.92 carats, measuring approximately 33.50 x 6.40 x 5.30mm., completed by round brilliant-cut diamond shoulders; unsigned, attributed to Nardi; mounted in platinum.
Tourmaline is noted for the large range of colors in which it occurs, but blue is one of the rarest. Like most tourmaline, indicolite is strongly pleochroic, meaning it shows different hues when viewed from different directions.