Well here's a mystery. I am designing a magnetometer. It picks up, of course, magnetic fields. But as I pushed its boundaries -- ultimately nearing the sensitivity of a proton magnetometer -- it started registering magnetism in strange things. An example is this "Top Red" Apple. It is no mystery that apples are diamagnetic -- which means that one may induce magnetic fields in them. But I wasn't inducing anything. Or was I? OBSERVATION: Does anyone have an explanation? I have a few possible explanations -- but I should have only one!