From the marks on the artifact, it was from an aircraft flown by pioneer aviator Horace Kearney, who was associated with Curtiss and Benoist aircraft powered by Hall-Scott engines. It is therefore likely that this a Hall-Scott propeller.
The Hall-Scott Motor Car Company, founded in 1910, built powered rail cars, as well as airplane engines. A few automobiles also used Hall-Scott engines. Elbert Hall was a principal designer of the famous Liberty engine, which was mass produced for World War I. Hall-Scott’s aviation business ended in the mid-1920s.
The artifact is from the collection of Mary E. "Mother" Tusch who, as a result of her motherly association with pilots who trained near her home at the U.S. School of Military Aeronautics at the campus of the University of California at Berkeley during World War I, became an avid supporter of aviation and aviators for much of the 20th century.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.