To the Sun - Mercury is never that far away from the Sun so doesn't get to form hard aspects. A conjunction under 5 degrees can make it very difficult to be mentally objective; the mind can't get far enough away from the self to see things from another's perspective. If the Sun is in Gemini and Mercury is in Cancer, rather than being the proverbial chatter box you will tend to talk at home and to those you know well, but strangers are unlikely to spot your Gemini straight away.
The Moon - When an easy aspect occurs between the Moon and Mercury it indicates a smooth flow between thinking and feeling; there tends not to be any conflict between the two, but it can also mean you are not so quick to sort out difficult situations. With the hard aspects, there can be a battle that takes place between the head and the heart forcing you to think things through until you are certain you are making the right decision. You tend to be slower to commit yourself mentally or emotionally and as a result, make less costly mistakes.
Venus - these two are not usually that far apart either and can never form a square to one another. The possible aspects are the conjunction, sextile, quintile, the semi-square, and semi-sextile. A conjunction to Venus may make it easy for you to tell others what you like and you will tend to be quick to verbalise your thoughts to those you love. The semi-sextiles can be difficult as the signs have a different temperament whereas the sextile itself is much easier. If you have a Taurean Mercury with Venus in Cancer, the elements can blend well, but take that Taurean Mercury and give it Venus in Gemini, and it will reject the Gemini lightness and unreliability as it goes against the Taurean fixed nature making it much harder for Venus to be expressed positively.
Mars - These are the aspects which decide whether you just like winding someone up or whether you are argumentative and like to have verbal battles and conflicting opinions. A conjunction almost certainly implies you argue or disagree for the sake of it at times; the trine may manifest as an ability to debate, the square and opposition will both cause problems, but you will probably find it's others opposing your ideas or views. Your thoughts may constantly be bombarded with conflicting voices, and the internal dialogue could be aggressive at times.
Jupiter - Okay, with the conjunction these can be the ones who talk loudly or sound very jovial, they may even boom when they say hello. With hard aspects they may exaggerate and know what is best for everybody. The thought process is usually quick and expansive; they will rarely look for details unless other factors in the chart can help. Jupiter in aspect to Mercury types will tend to talk over people quite easily. There could be a restlessness, a love of travel, or an interest in religion and philosophies.
Saturn - This can work in a number of ways, but with the conjunction, it will almost always constipate the thought process which can be good if the combination is in an air sign as it will stabilise them considerably. Saturn is never the best planet to have sat on anything, yet it will provide mental discipline and a sense of responsibility towards learning. The downside is it could be hard to have a laugh and just relax with thoughts of duties coming into the head at the wrong moment. With the opposition, you may find that external circumstances or people almost prevent you from unleashing your full Mercurial potential.
Uranus - The so-called genius. With the conjunction, the mind is very intuitive and if allowed to roam will give flashes of insight and creative solutions to problem solving. With the hard aspects, the abilities are still there but with obstacles and oppositions. This is a mind that does not like nor need to be restrained, and they may have problems within normal academic settings.
Neptune - The daydreamer and mystical thinker who likes to float off! With the conjunction, it can be hard to speak to concrete truth, and they may be prone to deception from themselves and others; some claim this is a liar aspect although I'm not so sure. I think it is fair to say they will frequently be found living in lalaland, but if it can be channelled effectively, it is incredibly creative. The trine will provide similar results but are more likely to integrate some form of mysticism into the life. The hard aspects will give frustration at times as Mercury looks for the facts, Neptune is throwing the blanket over his head. Both planets need to be satisfied somehow to get the best results from this combination.
Pluto - The psychologist or criminologist. The mind is penetrating and deep; it can't be arsed with superficial banter and wants to know the truth, the whole truth and nothing but the truth. Crime writing would suit as a hobby or profession; research and even medical stuff will appeal. One thing's for sure, this Mercury needs to be working, and if it is allowed to be idle, it'll be one vindictive bastard. Even the hard aspects will work well with Mercury and will add an extra element of compulsion in finding the answers it seeks.
Mercury conjunct north node; Mercurial abilities must be developed to evolve and grow in this lifetime. There is some special purpose involved in it all.
Mercury conjunct the south node; a possible history of gossip and mockery. Issues with siblings or neighbours, the rest of the chart will reveal more.
A note on Chiron:
It is possible that there is a wound around communication or learning itself. Confidence could be low; I'd like to say that healing needs to be sought, but I know that sometimes all we can do is learn to live with ourselves and carry on in spite of our thoughts, it's a case of feeling the fear and doing it anyway. Chiron indicates a wealth of knowledge in the chosen field and in aspect to Mercury there could be a calling to work with those with learning difficulties, speech therapy, or even those who have experienced sadness or wounding through brothers and sisters. For your own sanity, figure it out and do your bit.
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