Proto-North Caucasian: *Gĕrkwe (~-a)
Meaning: skin, sheepskin
Notes: Phonetically the correspondence is satisfactory (in Nakh *qaqa- with double assimilation < *ʁaqa- < *ʁaka-, a usual process when we deal with a combination uvular+velar within one root); but since the etymology is a Nakh-Lezg. isogloss, it is not very reliable.