NOVELTY - Formation of material comprises placing a first substrate in a reactor; placing a second substrate in the reactor; directing a precursor gas into the reactor; activating an induction coil proximate to surfaces of substrate to dissociate the precursor gas; depositing a constituent of precursor gas on both surfaces; receiving heat radiated from first surface and constituent deposited on first surface; and receiving heat radiated from second surface and/or constituent deposited on the second surface.    USE - Method for forming a material used to produce a structural building block and/or an architectural construct, as well as clean burning hydrogen fuel from a hydrogen donor.    ADVANTAGE - The induction techniques can be used to dissociate a hydrocarbon into hydrogen and carbon, with the carbon deposited on a substrate to form a useful durable material, and with hydrogen removed for use as a fuel.    DETAILED DESCRIPTION - Formation of material comprises placing a first substrate in a reactor, the first substrate having an exposed first surface; placing a second substrate in the reactor, the second substrate having an exposed second surface facing toward the first surface; directing a precursor gas into the reactor; activating an induction coil proximate to the first and second surfaces to dissociate the precursor gas; depositing a constituent of precursor gas on both the first and second surfaces; receiving heat radiated from at least one of the first surface and the constituent deposited on the first surface, at least one of the second surface and the constituent deposited on the second surface; and receiving heat radiated from at least one of the second surface and the constituent deposited on the second surface, at the first surface and/or the constituent deposited on the first surface. An INDEPENDENT CLAIM is included for a reactor system (100) for forming a material comprising a reactor vessel (111) having a reaction zone (123); an induction coil (120); a reactant supply; a first substrate support (114a); and a second substrate support (114b).    DESCRIPTION OF DRAWING(S) - The drawing is a partially schematic illustration of a system having a reactor with facing substrates for operation in a batch mode.    Reactor system (100)    Reactor vessel (111)    First substrate support (114a)    Second substrate support (114b)    Induction coil (120)    Reaction zone (123)