An Etymological Dictionary of the German Language/Annotated/Harz
Harz, neuter, ‘resin,’ from Middle High German harz, neuter and masculine, ‘resin, bitumen,’ with the variants hars, harse; Old High German harz, and with a suffix harzoh, ‘resin’; Dutch hars, feminine, with an abnormal s, but Low German hart; unknown to English and Scandinavian as well as Gothic; of obscure origin, scarcely allied to Greek κάρδαμον, ‘cress,’ For other Old Teutonic words with the same meaning see under Bernstein and Ritt (also Theer).