Cindy found this one, The Light at Tern Rock by Julia Sauer, a Newbery Honor Book in 1952–and originally published in the Horn Book Magazine in 1949. This would seem to break the award’s rule about “original work,” that the “text is presented here for the first time and has not been previously published elsewhere in this or any other form.” But maybe the rule was different then? Or perhaps here as so often, he says, drawing his emeralds warmly about him*, the Horn Book was above any such petty restrictions as criteria.
K.T. Horning, do you know?