Akkadian

ṣūru - cliff, rock (Streck 2000:117)

M. Streck (2000:117) considers ṣūru ‘cliff, rock’ in an OB Gilgameš tablet from Tell Harmal a WS loanword, but a rare but authochnous Akkadian lexeme cannot be ruled out completely (Kogan 2015: 203)

PCS
*ṯ̣ūr- - mountain (Kogan 2015: 203; Kogan 2011: 190)

no trace in Arb, unless one compares ḏ̣iˀr- (pl. ḏ̣uˀār-) ‘the three stones upon which the cooking-pot is placed’