Gemini
Gemini is mutable air, the third tropical sign. The Sun enters it as spring turns toward summer in the northern hemisphere, and the sign's job is adjustment: naming, carrying messages, and keeping two ideas in the air at once. The image is the twins. Two is the smallest conversation. Gemini is the sign of that conversation, of the road between one place and the next, and of the hand that writes it down.
Mutable signs change and translate. Air signs do their work in speech, thought, and the space between people. Gemini is both, so its weather is quick, local, and curious. Classical temperament calls air hot and moist. Heat moves. Moisture connects. The combination wants contact, variety, and a word that is accurate enough to send. It tires of a single story that refuses a second example.
Mercury rules Gemini, and Mercury also rules Virgo. In Gemini, Mercury is in his air domicile: language as trade, wit, and short travel. The same planet in Virgo is in his earth domicile and in his exaltation, a more editorial craft. Gemini's Mercury gathers and connects. He is less interested in the final edit than in the living exchange. Jupiter is in detriment in Gemini, opposite his domicile in Sagittarius. A wide, believing, doctrinal style fits this sign's weather poorly. Gemini would rather hold two reports than swear to one creed. That is a difference of method, not a failing of faith.
There is no classical exaltation assigned to a degree of Gemini in the standard seven-planet scheme. The sign's dignity story is mostly the domicile of Mercury and the detriment of Jupiter. When you read a planet here, you are reading it in a messenger's climate, whether or not that planet enjoys the climate.
The natural house is the third: siblings, neighbors, letters, skills of the hand, and short journeys. A planet in the sign of Gemini is not automatically in the third house. The sign says the style is mercurial and double. The house says which room of life uses that style. Gemini on the third is the textbook arrangement. Gemini on the seventh describes a partnership conducted as a conversation, and it still needs a birth time.
Sun in Gemini makes the conscious will curious and verbal, often thinking by talking. Moon in Gemini makes the feelings move quickly and look for a name. The feeling is real. It arrives as a sentence, a joke, a change of subject. Mercury in Gemini is the ruler at home. The Ascendant in Gemini makes the entrance light, alert, and hard to pin to one introduction.
Gemini squares Virgo and Pisces, and it opposes Sagittarius. The opposition is the pair of the nearby fact and the far meaning, the messenger and the judge of belief. Trines run to Libra and Aquarius, the other air signs, where talk recognizes talk. The gift of that trine is range. The risk is a cleverness that never lands.
In practice, ask what is being carried, translated, or paired. Gemini is honest when it is allowed to be more than one thing, and it goes thin when it is forced to pretend the second thing was never there. For the ruler, read Mercury. For the opposite sign and the wide view, read Sagittarius. For letters and neighbors, read the third house.