This image illustrates the use of the technique called “dragging the shutter”, combining ambient light with flash to have the “diamond” frozen in the air leaving a trail of movement going upwards that gives the impression of a magic levitation trick.
(tech info: 2 speedlites in softboxes at both sides and behind the subject, 1 speedlite on the background. Synchronized using a voice-activated shutter release. Canned mist for the mystery ambient)