I think that dust starts to assemble around a seed asteroid and that. emergent energies [for emergence see www.santafe.edu self assembling autocatalytic polymers stuart kauffman] atoms begin the be created and recreated by the local cauldron of the ether ... these new atoms would tend to be around the centre of the periodic table - the germanium etc light metals of semiconductors ..

so I think you get a rock coated in light metal salts which eventually acts as a capacitor which when driven by the star causes ignition.