The Astrological Symbol of Gemini is the Twins. Like twins, Geminis often have a dual nature and are skilled at seeing both sides of a problem, but they may also be fickle and restless. They are changeable and sometimes noncommittal. In this way, Gemini exemplifies the Mutable Quality assigned to it. They are adaptable and able to tackle multiple tasks simultaneously, and they know how to reason with people, but they may lack follow-through or seem ungrateful. Within the Zodiac, Gemini is opposite Sagittarius, the Sign of Philosophy. While Sagittarius tends to have one major interest that is studied deeply, Gemini people tend to have many different interests they study in less detail. They love to learn, and are analytical and versatile, but their study may be more superficial than in-depth.

Gemini is ruled by the Planet Mercury. In ancient Roman mythology, Mercury (and his Greek equivalent, Hermes) was the Messenger God. He was associated with travel and transportation. He was a communicator, quick-witted and inventive, but he could also be a smooth-talker and get bored easily. As a Planet, Mercury is androgynous; Gemini is the masculine (or day) half and Virgo the feminine (or night). Both Signs rule by words and logic, not emotion: Gemini is interested in communication as a way of making friends and learning, while Virgo is more focused on the analytical side, understanding what people are really saying. Mercury's role as communicator is exemplified in Gemini. People born under the Twins are charming and congenial, and they often have many friends and acquaintances in all areas of their lives. If they aren't careful, they may appear to be scheming or gossipy. Their facility in adapting to new challenges may seem like opportunism. Their interest in numerous subjects shows they are adaptable and curious, but they may seem like they lack concentration of have difficulty making decisions. Geminis who learn to focus and use their intellect in one area, instead of fidgeting, tend to be very successful.

The Element associated with Gemini is Air. Air Signs are intellectual: they tend to respond to the world through intellect, rather than physical action, practicality, or emotion. When presented with a new project, their mental abilities kick in and they join the group enthusiastically. While they don't tend to be leaders, their facility for abstract reasoning and broad-minded outlook enables Geminis to make strong contributions to projects they work on. Their logic and objectivity may help them see past roadblocks caused by emotional conflicts among others, but their intellectual orientation may seem cold and impractical to some. It is important for Geminis to learn that their love of knowledge can be compromised by their short attention span, but their awareness and intellectual approach to life can assist them.

As the Twins, Gemini is the Sign of brothers and sisters as well as communication. They often remain youthful and lighthearted for their whole lives. Cars and short trips are also ruled by this Sign, and many Geminis are mechanically inclined. They are more likely to be ambidextrous than other Signs, and can be inconsistent. Because they are "of two minds," people born under Gemini may tend to shift interests and seem scattered and high-strung. Their many interests, however, makes them entertaining and stimulating conversationalists with a carefree and unpredictable twist.

In their leisure time, Geminis tend to enjoy pairing up with a partner for recreation. They often have a fondness for tennis. Their love for conversation ensures that leisurely dinners with friends are highly enjoyable for them, and their inquisitive and literary orientation means they enjoy mentally challenging pursuits as well. In love relationships, Gemini is caring, flirtatious, and playful.

Gemini rules the collarbone, the arms and hands, the lungs, and the nervous system. People born under Gemini may suffer from wrist problems, such as carpal-tunnel syndrome, respiratory ailments, and nervous conditions more often than people born under other Signs. Gemini's colors are yellow and sky blue, the color of Air.

The great strength of the Gemini-born is in their intellectual and conversational skills. They can analyse difficult ideas and communicate them clearly to others. Their many interests put them among the most fascinating characters of the Zodiac.