If you have been following my posts here you probably realized that the availability of tourmaline and its affordability have pushed me to cut practically everything in tourmaline that I have. Years ago I purchased a significant lot of “mine run” tourmaline from Afghanistan for reasons that have long since disappeared. Even the dealer said that I would not be happy with such small rough, but that was only part of it. Most of it was fish gravel, but I cut small gems for a year without more investment.
One of the types of rough crystals of tourmaline that I shied away from was thin and with semi-closed ends. The rough was so small that if I made the crystal thinner, so I had the depth to cut an emerald cut, there would be nothing left and to cut a round with a large difference in tone level, seen face up, due to the dichroic nature of the rough seemed unbalanced. There was also no way that I could cut a practical round with the dark c axis (principle axis) perpendicular to the table.
So a good part of the small percentage of the lot that was facetable has sat uncut for years. Now the c axis can have a nice color and it would certainly dominate any stone that was cut from the rough. And cutting a small stone does not take a great deal of effort, so why not try cutting the “impossible” crystal. After suffering the usual problems with handling such a small piece of rough and using alumina to make my meets, I was pleased with the round I produced. (I made a round because it is the thinnest practical faceting cut.) The rounds 4 mm diameter had opened up the semi-closed c axis to a nice darker blue and the a/b axis was flashy. I can still notice the band of lighter more reflective facets in medium to lower light conditions, but in full sunlight, the whole stone flashes a medium rich blue color without noticeable dichroism.
(This whole story is similar to an effort I posted about with a much bigger round that was included, while my little piece was flawless. Being flawless and making the orientation of flaws, a critical step in getting decent gemstone out of included rough, unnecessary, a long with decent color, were the only reasons the rough was even worth trying to cut.)
I am still looking forward to a new lot of rough from Africa any day, but my little stone did confirm my growing confidence in handling semi-closed, yet colorful tourmaline, without cutting an emerald cut with steep ends.
Bruce
