Maybe the speed was the issue, I did keep it slow to avoid heating of the tool, but it might have set me up for the brittle explosions I dealt with.
This is actually a pretty good fit in the hand, and bowl, even though not what I set out to make. And definite tortoise type look so I might order some more of it. The thinner profile of the finished handle helps the shading shine through.
Thanks for the feedback gents.