Correct spelling for the English word "zundererz" is [zˈʌndəɹˌɜːz], [zˈʌndəɹˌɜːz], [z_ˈʌ_n_d_ə_ɹ_ˌɜː_z] (IPA phonetic alphabet).
Tinder-ore; an ore of antimony occurring in soft, flexible, tinder-like masses, of a blackish-red colour.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.