Planet
Mercury
Mercury is the traffic in a chart: what comes in as information and what goes back out as speech. In matters of career it stands for voice, communication, the way you frame what you do.
The tradition places it at home in Gemini and Virgo, exalted in Virgo, in detriment in Sagittarius and Pisces, in fall in Pisces.
Read that arrangement closely and Mercury doubles at both ends. The sign it is exalted in is also one of the two it rules; the sign it is said to fall in is also one of the two it is uneasy in. Elsewhere in the classical table the strong signs and the difficult ones sit apart, so Mercury's extremes are unusually concentrated — whatever it is good at and whatever defeats it, it is the same terrain twice over.
Two homes, two different minds
The two signs Mercury rules describe two uses of one faculty. Gemini collects: it moves fast, holds several things at once and is interested in the next one. Virgo corrects: it slows down, checks the join and is interested in whether the thing is actually right. A chart leans to one, and the other is still in there — most people can hear both in themselves depending on the hour.
Mercury is counted among the personal planets, quick enough to describe a person rather than a stretch of history. It also never strays far from the Sun, so it sits in the Sun's sign or a neighbouring one and in a great many charts the two are in the same place.
A faculty that close to the identity it serves is hard to separate from it. What a person thinks and what they take themselves to be come out in the same voice, and prising the two apart is real work rather than a turn of phrase.
Voice, and why it is a working matter
Of everything a working life runs on, Mercury holds the parts made of words: the pitch, the brief, the explanation given a second time because the first one did not land. How a thing is framed decides more of its reception than most people care to admit, and framing is a skill rather than a temperament.
The sixth house is where that is least glamorous and most visible — routine, service, health, the apprenticeship layer of work. Craft is mostly repetition with small corrections, which is Mercury's more exacting home doing its job under another name.
Being good with words is not the same as being right, and Mercury is indifferent to the difference. It is a transport system. What it carries is decided elsewhere.
Retrograde, and what the word marks
Mercury retrograde has escaped astrology and become a figure of speech, which has done nobody any favours. A retrograde station is described as the moment a planet appears to stop and reverse direction, marking an inward, review-flavoured phase; a direct station is the moment it stops again and forward motion resumes.
Appears is the operative word. The planet does not turn around; its track against the signs reverses from where the Earth happens to be standing. Astrologers read that apparent reversal as a change of direction in the faculty rather than in the sky, which is why the same word covers a planet and a mood.
What it is not is a licence to blame a lost email on the calendar. Read plainly it is a stretch in which Mercury's own business — drafting, deciding, agreeing terms — tends to go better on the second pass than the first.