Over a year ago, my principle dealer in Africa said that he had just gotten a nice piece of cuprian rough tourmaline that probably came from a new location for cuprian in Mozambique. I thought that I had read a brief note about an undisclosed location in Mozambique that was producing a little material and that it was Liddicoatite not Elbaite. This made the piece very interesting to me, but you can seldom be positive about the origin of rough from Africa. (In the time, since he obtained the sample, he has not been able to get more material. So it appears that whatever locations that my new piece came from will not develop into a major find.)
Now I am not saying that some tourmalines like “sunset” tourmaline and “chrome” tourmaline don’t come from well known locations, but generally new deposits are deliberately kept secret if possible. Mavucu, the only documented source for cuprian tourmaline in Mozambique was kept under raps for years. This could have been because of questions about the land with the government, taxes, etc. or simply the desire of the owner not to have dealers/wholesalers provide a tempting outlet for stolen material. This reluctance to reveal locations for sources of tourmaline rough is compounded by a great deal of variability in many of the individual deposits of tourmaline. A final point is that the rough will be declared to come from a location, that is known/hot, if that increases its desirability and commensurate price. This has lead my principle dealer in African to not declare the country of origin for most of the tourmaline rough he sells, even when he has an educated opinion.
Superficially the 13 carats specimen could have come from Mavucu. It is completely and deeply water worn as all cuprian rough I have gotten from Mozambique has been. It appears to be a chip caused by the conchoidal fracturing of the original crystal. The side of the original crystal provides a naturally flatter surface that should make an ideal place for the table. It does not have any rind and its general outline is that of a tear drop. Even with the the advantage of an exceptionally well shaped nascent table and outline, the rough is relatively thin and that will probably take a toll on yeild. Its has a plume color of moderate tone value that is certainly related to other cuprian material, but it is probably not identical to anything in my collection. This is not enough to declare that the rough comes from a different deposit, but its dichroic nature is quite unusual for cuprian tourmaline from Mavucu. And the dichroism is moderately strong. The strongest tone values are down the axis of symmetry going thew the point of the tear drop rough. It does not appear to be of a significantly different color than the a/b axis colors. I don’t think that it will be too dark for such a small stone, but time will tell. I am still not sure what its final shape will be and even its final size since surprises can hide inside a frosted, water worn nodule.
I will try and get some pictures for your enjoyment.