Mercury is the communicator. It rules the mind and how the person thinks, based on the sign Mercury occupies.
Mercury is the ruler of sharp, chatty, superficial Gemini. The idea-man/woman. Brilliance. The multi-layered actor.
The traits of the sign Mercury occupies will describe how a person’s mind works. The signs Mercury rules (Gemini and Virgo) are the fast thinkers and extremely intelligent—if not a touch nervous.