Stunning, beautiful and incredibly rare!
Normally I would not write a section on a specific gemstone from a specific mine, however, the Rubellite I have seen from the Cruzeiro mine is amongst some of the finest I have ever seen. Whilst the crystals may not be as big as some of those from other Tourmaline mines around the world, the quality of the gem’s clarity is simply staggering.
As Tourmaline is the most dichroic of all gemstones, Rubellite is never a pure red and is always a blend of purple and red, or pink and red, and sometimes all three. Whilst Cruzeiro Tourmaline can be found in all three hues, more often than not they tend to lean towards the more reddish pink hue.
Rubellite is more of a description the trade use to describe a Tourmaline that has the presence of a red hue. Most gem laboratories however will tend to name the gem either a pinkish red Tourmaline, a reddish purple Tourmaline etc.
In terms of value, the closer you can get to a pure red hue, the more valuable the Rubellite becomes, but as mentioned above, as the gem dramatically splits the light in two as it enters the gem, it is almost impossible to find a piece that is pure red. The closer you get to a Ruby red the more the value increases. Unlike Ruby, treatment of Rubellite tends to be restricted to just heat treatment (to reduce the tone) and irradiation, making the gem far rarer than its better know counterpart. When valuing it is important to remember that you will seldom find an eye clean Rubellite and the more pure a red hue, the more likely you will find inclusions. In terms of pricing, weights over one carat increase dramatically in what I refer to as a “hockey stick” price curve.
As mentioned above, what tends to set Cruzeiro Tourmaline apart from those found in other locations is its stunning clarity. Marcelo, the mine’s geologist, explained to me that this was primarily because the geological conditions where the gem was found in the Cruzeiro mine was less hostile than the growing conditions in other locations. He also explained that in terms of colour it was impossible to say whether a certain specimen was from a particular locale based on its colour, as all Tourmaline mines tend to produce Rubellite with an array of tones, but he could often spot a piece from the Cruzeiro Mine based on its clarity.
Of course, you do have to realise that in the gem industry miners, geologists and us gem hunters will always be slightly biased with our opinions. That said, I do try and keep a balanced opinion and even though I buy and sell Emeralds from all over the world, I will always have a personal preference for the clarity provided by Zambian Emerald (unless of course we uncover better in the future) and likewise I will always have a leaning towards the incredible clarity and diaphaneity offered by the Cruzeiro Rubellite.