Douglas Harper's Etymology Dictionary
c.1400, "to splinter, chip" (transitive; spalding-knife is from mid-14c.), of uncertain origin, perhaps from Middle Dutch spalden, cognate with Middle Low German spalden, Old High German spaltan, German spalten "to split" (see spill (v.)). The later form of the verb is spall (1758), from or by influence of the noun. Related: Spalled; spalling.