The material basis of the stone actually is a composition of pure chemical substances. The practical problem is, that only certain chemical substance classes are suitable to function as magnets in reference to the vitality. There are only certain organic and inorganic compounds, which own these characteristics. But only certain matters have the necessary characteristics to exercise the magnetic effect. In this case there are natural sources, which have a certain magnetic power.
Some minerals are magnetic.
Today no man would have the idea laying down a piece of iron in front of him and magically trying to produce an effective magnet from it. Who knows the physical-chemical conditions, which make out a magnet, can manufacture a magnet, in that he processes suitable raw materials. The magnetism is a characteristic of matter. The necessary mental effort of man only is to rearrange matter in a way that the magnetic power in nature can appear. The practical alchemist can do exactly the same.