An Etymological Dictionary of the German Language/Annotated/Schein
Schein, masculine, ‘shining, sheen, semblance, appearance,’ from Middle High German schîn, Old High German scîn, masculine, ‘lustre, shining, brightness, clearness,’ late Middle High German, also ‘evidence, testimony, appearance’; compare Old Saxon skîn, masculine, ‘lustre,’ Dutch schijn, Anglo-Saxon sčîn, ‘ghost.’ An abstract of scheinen, verb, from Middle High German schînen, Old High German scînan, ‘to glitter, appear; show oneself’; compare the equivalent Old Saxon scînan, Dutch schijnen, Anglo-Saxon sčînan, English to shine, Old Icelandic skína, Gothic skeinan. The Teutonic root skî, whence skînan, strong verb, is formed with a present suffix na-, appears with a suffix m in schimmern. Akin probably to Greek σκιὰ, ‘shadow,’ see Schemen; also Greek σκίρον, ‘parasol’?. See schier.