Russian 14K Gold Ring with Ruby

[Cantiq]

Hi,

I am looking for help to determine both - age and the jewellers it comes from.
I know it is Soviet 14K.

Stamps are minimal, but I tried to use the microscope to make it clear.





Thank you for help.

[teh]

If the first number in the first picture is a 6 (that's what it looks like) it's from 1976, assayed in Baku. The maker is either IO or ю.

Good luck!