The identifying characteristics of a genuine Stiffel lamp include a signature foil decal or etched mark on the lamp's base, a decal inside the lampshade, and the unique design of the Stiffel light switch. Weight is another indicator, as authentic Stiffels tend to be heavier than replicas.
An authentic Stiffel lamp can be identified by a foil decal reading "SLC," "Stiffel," or "Stiffel Lamp Company" on the base or shade. Alternatively, the identifying mark may be etched directly onto the base. A label may also be present on the light socket. In addition, older Stiffel floor lamps have a unique switch that requires the user to pull down on a section of the lamp's pole.