Hovering Crystal: Skeleton Key, Part 2

From The Angel of the West Window, a 1927 novel about the life of John Dee by the German occultist Gustav Meyrink:

The crystal was hovering somewhere in the darkness above me. A dull ray emanating it from it struck my forehead and I had a clear sensation that this established some significant relationship between my head and the stone. I felt afraid, and tried to withdraw by turning my head from side to side, but I could not escape the ray of light . . . Slowly, slowly the crystal floated down from the heights above me and came close to the top of my head. And I had the feeling that the stone was something alien to me, so utterly alien that I could not put it into words. Some object from a distant galaxy could not have been more alien. I don't know why, when I think of the dream now, I think of the dove that descended from heaven when John was baptized.