This large oval has a nice purplish red flash driven color. It is eye clean and with fine crystal. Its cuprian nature has been confirm with a spectrometer. It weighs 13.94 carats.
A large water worn pebble was offered for sale and was not getting any takers. It has a reddish color with an overtone of purple, but its tone level was dark. Now I don’t have any of my stone treated and I stay away from really dark stones that I would have to cut up to make smaller gemstone with less intense color. But I could sense the present of copper and perhaps I could keep it in one piece. I could always fall back on cutting it up, but you always loose a lot when you have to use the saw, no matter how thin it is.
When I got the rough I knew it was marginal and I set out to cut as thin an oval as I could with appropriate angles. I used two rows of step facets on the top to control the crown’s depth, after leaving the crown as thin as I felt comfortable with. It is certainly not as thin as some commercial oval that have seen recently. I wanted a thin stone, but not a freak.
So when it came off the dop and gave me bright flashes of purple red which signaled success. I had to give it a name. And so she became prized plume, but there was still a question about her patrimony. Did nature give this beauty a touch of copper or was she the more common purple red that many people treasure and call rubellite? Well my spectrometer proved to be inadequate for the job because of complications from the absorption by manganese, but I still needed to know.
I was bound for Alabama with my prized plume on my knee, to work with a professor and his more inclusive spectrometer. It did take quite a bit of time to integrate the absorption signals into graph without to much scatter, so I could only test a relatively few stones. And prize plume was one of them. And she revealed her true self to be cuprian. I really didn’t think that she was just color by manganese, because the purple overtone is just not right, but it was great to see science confirm it.
I know that I did not put cuprian in the title because she wishes to be appreciated for her beautiful flash driven color without the chemical angle, but you deserved to know, if you got down to the bottom of this long post.
Bruce.
