My specialty is cutting Sapphires and I am busy cutting away on some beautiful Australian top color blues and blue/greens right now. I also have lots of scheduled cutting tasks ahead of me, as I have Montana sapphires on the dop, just waiting for me…..
Too many stones, too little time!
When we got our Tunduru/Songea sapphire roughs, I went through them all by checking out the quality, what silk was in them, what percentage couldn’t be used and weight. What I discovered was that we got lots of color changing stones.
My method when cutting these sapphires is to roll the stone on a flat surface and whatever side comes to rest down, becomes the table of the stone. I usually cut the crown first, which is a little unusual as this is the placement of “meetpoint” facets, but if it was good enough for the Diamond Cutters, it’s good enough for me.
By cutting the crowns first, I had been able to improve my recovery to 15 to 20% more than using the meetpoint method of cutting the pavilions first. I know many people may disagree, but it works for me!!!
The Tunduru/Songea sapphire roughs go from a dark purple under Halogen to a Kashmir blue under Fluorescent to a beautiful blue/green in daylight. Sapphires are what I enjoy cutting the most while beryl and kunzite are the least liked specimens!!!
I also use a piece of clear optical quartz when perfecting a new design. Some people feel that using Citrine, Smoky Quartz or Amethyst is good enough for this, but I took some advice from some great people (Bob Johnson, Bob Wilson and Bill LaCombe) when I was just getting started, and that was to buy the best quality rough I could afford.
As a result, we don’t use Citrine, Smoky or Amethyst, as the rough is too fine quality to practice on. We used clear marbles and glass which are great to practice on because they are soft and easy to see where you’re off on your cuts.
I can’t stress enough for faceters to learn to cut both ways, crown first, pavilion first as it makes you more confident and more proficient at your cutting. Although it can get really messy and you get a purple stain over everything, I usually give that to my beginner students to get them started.