Gemini
Gemini is a mutable air sign ruled by Mercury. Astrologers associate it with curiosity, talk and quick thinking, and with a restless interest in how things connect.
- Dates
- About May 21 to June 20
- Element
- Air
- Mode
- Mutable
- Ruler
- Mercury
- In detriment here
- Jupiter
- Opposite sign
- Sagittarius
In the tradition
Gemini closes the spring. Ptolemy calls the last sign of each season "bicorporeal", or double-bodied, because it sits between two seasons and shares something of both. The twins in the image are usually Castor and Pollux, the brothers of Greek myth who shared one immortality between them.
Ptolemy gives Gemini to Mercury. The traditional scheme gives it no exaltation. Medieval astrologers assigned it the shoulders, arms and hands, which fits a sign so often linked to writing, trade and dexterity.
Strengths and shadows
The gift of Gemini is a quick, sociable mind. It learns fast, sees more than one side of a question, and can make a stranger feel like an old friend over a single conversation.
Its shadow is scattered attention. Gemini can start ten things and finish two, argue a side for the pleasure of arguing, or keep things light when a situation needs weight.
In close relationships Gemini is said to want a partner who is also good company in conversation. Boredom tends to worry it more than conflict does.
In a birth chart
Whatever planet sits in Gemini tends to speak through words, ideas and variety. Mercury is at home here. Jupiter is in detriment, which older authors read as broad wisdom broken into facts and opinions.
In the modern pairing of signs and houses, Gemini corresponds to the third house: siblings, neighbors, short trips and everyday communication.
In a Caelumia profile
Caelumia reads Gemini toward these themes, then weighs them with the rest of a chart and numbers before anything is shown: Curiosity, Expressive communication, Restlessness, Sociability.
Sources
- Claudius Ptolemy, Tetrabiblos (2nd century CE). The classical source for the tropical zodiac, sign qualities, rulerships and exaltations.
- William Lilly, Christian Astrology (1647). The standard English reference for traditional sign descriptions and essential dignities.
- Robert Hand, Horoscope Symbols (1981). A widely used modern account of what signs, planets and houses mean together.
Updated September 27, 2026.
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