Mercury is the smallest planet and the closest planet to the Sun. It rules Gemini and Virgo.
Mercury represents thought, communication, commerce, and learning. The Moon governs the unconscious mind, while Mercury rules the conscious side. It can also signify travel.
A person with a Mercury in Cancer may communicate very emotionally. People with Mercury in Taurus talk deliberately.
A well-placed Mercury can show up by intelligence, strong communication skills, and learning well on their own. An ill-placed Mercury can lead to being a good liar, mischievous, and having no opinions.
"As long as the process of knowing is recognized to be less important than that which is to be known, Mercury is one of the highest symbols of all." Robert Hand - astrologer