What can a gaussmeter tell me about a metal? I am just experimenting with various metal disc samples by setting them on the Hall probe of a gaussmeter. I have the meter zeroed out, then I pace the metal on the probe. The metals all effect the field measurement in different ways, but I don't know the mechanism at work. I assume that if the metal is at all ferromagnetic then it has its own field? What about other diamagnetic or parramagnetic. Does any one care to give me the 9th grade explanation.