I just finished doing an Arizone Jade Gemstone. I am assuming they are the same.
My first Gemstone was a Black with Gold Matrix. Everything was working fine, I was turning just as I normally do, just slower. Suddenly just as I got close to the bushings a huge chunk got knocked off. When I picked it up, it was hot enought that it suprised me into dropping it. I have to agree that heat is your enemy I am sure that the heat caused expansion and a small crack which the skew grabed. Luckily when everything cooled, I discovered the piece could be glued back in with an almost imperceptible crack. There is a picture of that pen in the gallery.
http://www.penturners.org/photos/index.php?n=14140
The AZ Jade was my second Gemstone. With the AZ Jade, I did about two passes with the tool. I then paused (leaving the lathe running) to give the tool a quick hone on my Worksharp. This seemed to give just enough time for the blank to cool down.
Pen turned out beautiful. I know "No picture, it didn't happen."
I gave it to the client before taking a picture. However, as I work with this particular client, I can get picture as soon as he is back from vacation.
Overall, I love this stuff. Comes out to a high gloss and has a very classy elegant look.