I found what looks like a rock.  I need some help to determine what it might be.  It is not lead as it is too light.  It weights only 14.4 grams.  It is NOT magnetic.  The VDI is +80 (with 87% confidence) and the polar graph has all three frequencies in the upper right quadrant, so it should be something good.  I suppose that there could be a coin completely encased in this rock-like material but it's hard to imagine given the apparent hardness of the material.  Any ideas would be greatly appreciated.