MERCURY

Isn't the word 'merkuri' a Georgian adjective formed out of a 'merke' noun? It well may be.

But what is 'merke' then?

It's მერქე - 'a horned man', a trademark Georgian 'me + <root> + e' personificating construction, derived from რქა (rka) - 'horn'.

Was Mercury horned? Yes:

'...But it also has curved horns coming from the top of the circle. This is the medieval alchemical symbol for Mercury, and has been used for thousands of years..'. http://www.universetoday.com/14019/symbol-for-mercury/ 

Those who still doubt, have a look at this:
https://ru.wikipedia.org/wiki/Меркурий_(мифология)