Flourite Ball

I went to visit some friends of mine tonight. They had a flourite ball on a table. I asked them if I could experiment by generating a spin field in it. They said they wouldn't mind. When I generated the spin field in the flourite, a strange thing happened. At first it was a fairly strong one-directional field. Then, suddenly the direction of the field shifted about 10 degrees counter-clockwise, as I was holding the field in the horizontal plane. Then the strength of the field dramatically reduced. Then, it began to change from a straight line, to a cone shape, centered on the new axis. Then the cone disappeared, and the spin field seemed to diffuse throughout the entire ball.

Have you ever encountered anything like this?