This amazing Dune painting of a "Fremen" according to his son likely dates from 1963-1964 based on on the artist's conception of the maker hooks....and though it has no record of it being published, probably was created for Analog and that it was either rejected, or he came up with a better idea.   Appears to be in gouache on board, and is unsigned.  Sight size is 17.75" x 14, on board 20" x 18" that's been matted to 24" x 20"  I have not removed the matte, to see what might be below (a signature?)  If you own compendium books on Schoenherr's art, c. 1978, this painting could be in one of them!