There are many common materials that are not attracted to magnets, water, wood, animals, plants... etc., however some of these non-magnetic materials actually repel magnetism.
Materials that repel magnetism are called diamagnetic, graphite and bismuth having the strongest effect.
The following page by Martin Simmons (UCLA) gives a good primer about diamagnetic levitation;
For a more indepth and scientific understanding, Martin's paper in pdf format;
Magnetic Levitation at your fingertips, gives equations and examples for magnetic levitation.
Reade Magnetic properties & susceptibilities chart gives a useful insight into the magnetic properties of different materials.
Cool experiments with diamagnetic materials and NdFeb mangets.
Fun with Diamagnetic Levitation
GerAx have some more good info;
GerAx - Diamagnetic levitation., check out their experiments, and levitation jig.
For some commercial applications of diamagnetic levitation, see;
Aussie Magnets' design portfoloi, the floating, working lightbulb is amazing!
After looking around at commercially available levitation jigs and materials, I thought Lego, being non-magnetic, would make a very good construction material for my jig.
I also found a supplier of bismuth - in shot form, a non-toxic replacement for lead shot in shotgun cartridges. The bismuth shot does contain some tin, however the shot is much cheaper than pure bismuth (£158 per kg from one source!) and works adequately.
I puchased a 3kg jug of shot, although your local dealer may split cartridges for smaller amounts.
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