Silver in Kurdish is "ziv".
That's also similar to the Northeast European and Basque term. As other Iranian languages use the PIE word, I would guess that Kurdish salvaged an indigenous word to West Asia. I also found out that the Akkadian word for silver was sarpu, related to sarapu "to refine, smelt", which is really close to the Slavic words (e.g. serebo in Russian). The Neolithic origin of silver is thus further reinforced.