The method of high-voltage breakdown in liquids and gases to obtain various types of nanocarbon with different structures and types of local atomic order is considered. The initial electron configuration of atoms and the structure of molecules in organic liquids—sources of carbon—is the determining factor in preparing the amorphous carbon with different types of local atomic order and specific electrical conductivity. The selectivity of the method of gas processing by high-voltage breakdown is also can be controlled by the choice of the chemical composition and morphology of the substrate material for deposition. The considered data are proposed to be used as a basis for an express method for assessing the type of nanocarbon, obtained as a result of the high-voltage breakdown of liquid and (or) gaseous carbon sources.