An Etymological Dictionary of the German Language/Schiefer
Schiefer, m., ‘slate, shist,’ from MidHG. schiver, schivere, m., ‘splinter of stone, and espec. of wood,’ OHG. scivaro, ‘splinter of stone’; the modern meaning is ModHG. only (in UpG. the prim. meaning ‘stone splinter’ has been preserved). Goth. *skifra, m., is wanting. Allied to ModHG. Schebe, f., ‘chaff, boon’ (of flax or hemp), which is derived from LG.; comp. E. shive (AS. *sčîfa); MidE. schivere (AS. *sčifera), E. shiver. These are derivatives of a Teut. root skī̆f, ‘to divide, distribute’; comp. AS. sčiftan, ‘to divide,’ E. to shift, OIc. skipta, ‘to divide’ (OIc. scífa, ‘to cut in pieces'; allied to Scheibe? or to this word?), Du. schiften, ‘to separate, sever.’ Schiefer and Schebe are lit. ‘fragment, part.’