Feature Article


Tanzanite, which is a variety of zoisite, has a Mohs hardness of 6.5 - 7.5 and my experience carving opal, of similiar hardness, made me think that carving would be easy and polishing a problem. Again, I was wrong.  The tanzanite was soft but very brittle and splintered frequently, making another problem for my hands which were frequently slivered and bled. Using using rubber wheels with silicon carbide worked best and as fast as diamond bits.

Many gems are a little forgiving when they get a bit warm.  Not tanzanite!   The slightest hot spot made a rainbow and fractured.  I used tepid water and persevered.

Because quartz is mixed with the zoisite, there are soft and hard spots which are side by side.  In almost every gem, the change from hard to soft or between colors is a danger area for cracking or splintering.   In the sceptered long part there were frequent blocks of differing colors and hardness. Chunks fell off and there were many splinters.  Finally the worst occurred; the piece broke at the middle.  I thought I would faint.

I was seriously involved with making this piece the very best I could as I wanted to be able to sell it to help my Maasai friends and when the piece broke I felt that I had ruined something which could be of benefit to them.  I wanted to cry.  Perhaps I did.

Ok.  Next.  I epoxied it back together and continued.  There were spots I didn't like and tried to cut through them to create a more beautiful line.  It was bizarre.  It seemed that I kept returning to the same shape over and over, only smaller as I cared the precious material away.  I could not get it to shape up the way I wanted.

Time was getting very short.  I had to start polishing, another challenge.  The rubber wheels were pretty good for smoothing the surface and I was using medium felts, not the hard or rock hard as they chipped the piece just as the wooden wheels did.  I used silicon carbide, lots of water and a slowish speed to avoid any heat build-up. On larger areas I went to very worn Nova wheels which were ok.

Finally, very slowly I used large medium and hard  felts, sometimes wooden wheels I made myself and diamond.  I used the wooden wheels to maintain the crispness of the open cells as I wanted them to stand out and not be observed as poor polishing.  The felts softened the edges of the cells, which I did not want and thus used the wooden wheels.  Sometimes it just got hot and that was that.  Back to the rubber wheels to remove the spot. Diamond up to 14,000 and then a touch with the 50,000.

The stand was a continuation of the flowing shape I had carved, cast in silver and blackened it with liver of sulphur to represent the black graphite the gem was found in.  I embellished it with silver satin polished fins to represent the wind from the Rift Valley.  The piece represented, to me, as I was carving it, a Maasai woman, her kangas (the skirts and wraps) flowing in the wind.  The uncarved natural termination became Mount Kilimanjaro which is on the traditional Maasai land in in constant view of the tanzanite mine.  I named it Maasai Skies.

Although this was a carving which filled me with despair, it was a Finalist at the IU Awards Competition and I look forward to selling it and sending the proceeds to the wonderful Maasai.  While I was at the mine I was given another 300 gram piece of rough which I had to carve with lightening speed for the same export reasons.  This piece caused me much less aggravation, first because I was now familiar with tanzanite’s nature and also because this piece did not fight me as the other one had done. Completed, it may be the world's largest tanzanite carving, finishing at about 150 grams and named L'Heuere Bleue -  the moment when the evening sky turns that wonderful rich blue-violet. This piece is currently in the AGTA Spectrum Awards Competition and I am hopeful that it will be a winner, and the benefits of sale also go to the Maasai of Tanzania.