This is a nice chord, one of my favourites (along with Bm/min, Gm, Dm, C#m, Emin and A#m). Of all the chords, sharp/flat, major and minor, this is the one I peg myself as.
If you read what I have below about major/minor differences on the previous posts, go ahead and skip this - it's just for newcomers reading this.
A note on major/minor:
There is an obvious difference between a major and a minor. Wikipedia naturally describes a minor chord has differing "from a major chord in having a minor third above the root instead of a major third." In other words, the third key from the first on a keyboard (not in the chord or scale) would simply be moved a key to the left. In C major, the notes are C-E-G. E is three keys from C; move one key to the left and you're now on E flat or D sharp. Hence C minor. The "minor third" just means the third note in a minor scale.
Ear-wise, the difference is also obvious because minor chords sound darker and moody and tentative while major chords are bright and happy and powerful in contrast. If you've heard any sad songs, they're likely built around a minor scale progression and use minor chords. 'Not Home Today' uses mostly minor chords (E minor and B minor) and is a song about an unfortunate circumstance, with a doom-filled ending. 'Around the Bend' uses largely major chords and is a happy song about friendship and good times. Of course, not all songs operate this way - 'I'm Sorry' by The Payolas has bright chords yet talks about a sellout musician. 'Alive' by Pearl Jam has what people have referred to as an anthemic sound, with great strong major guitar chords and progressions, yet it's about a man who discovers his father died long ago and his mother is virtually attracted to him thanks to his resemblance to his father.
The thing about inversions - where the root note is not the lowest or first note played in the chord - is that it's all the same for every chord major or minor: It's either darker or brighter, in terms of colour as well as personality (though slightly, and it's perhaps more on the main personalities' view or opinion or feeling on something).
Colour: Grass green. Particularly my memory of the green grass in the courtyard from my childhood in Parkwood Hills.
Light: From behind. Moderately lit - not bright nor dark.
Spatial Direction: East, typically.
Texture: Hard to describe. Not "grassy." Same as the pixels on our old TV (mother bought it in 1986). But horizontal as those pixels were more rectangular-shaped, vertically.
On The Signature Series, A major was feminine and portrayed as the bouncy, cute, sweet girl-next-door. You'd be charmed by her, but she'd always be looking for someone better, while on the move. The episode called it the "willow-the-wisp."
To me, A major is a shy, but bright person. Bright as in, he's not sad or down, but while he can have negative inclinations, he'll put a smile on his face more often than not. He has a mildly adventurous vision of things but tends not to actually be too adventurous in real-life - he's more of a dreamer. Very grounded, and thinks in concrete terms. He's not a leader, but he's also not much of a follower, tending to be more of an independent. He can be stoic - he often looks that way - but underneath he has a lot of hidden sensitivities that just haven't had a chance to come out as the right person to see it hasn't come along yet. He has a very strong sense of emotion and feeling, but it doesn't always show easily. One thing he does know, though, is that when he pairs up with someone, friend or more, that person will get the most consistent help, advice, and care. He cares about their well-being. He's quiet, but he has an endearing quality that's hardly matched. I tend to see myself as A major because I am similarly quiet and stoic-looking most of the time, but in my heart my close friends deserve best. While I may not have had a real girlfriend before (yeah, yeah) the one out west knows very well how immediate I tend to be with my encouragement and caring positivity. I know that making those I care about is what fulfills me, and that's A major. The verses of 'Steal my Sunshine' by Len start with A major (and end on B major). 'I Ran (So Far Away)' by A Flock of Seagulls, while not using the chord in particular, mostly stays on A throughout the whole song. 'Radio Silence' by Blue Peter starts on and remains mostly on A. 'Magic' by The Cars starts on A as well. I first felt that I was similar to A major thanks to another Cars song, 'You Are The Girl,' which has an obvious keyboard/bass bit where both just sustain an A for a second or two. I saw myself perfectly - I had a hard expression on my face, of waiting for an answer on something exciting. Like the question had been "are we taking this trip together?" and it had been to a girl. It's a good chord.
Light: From behind, but very dim
Spatial Direction: East, northeast
A minor was the "Faded Beauty" on The Signature Series, the older woman who'd let life pass her by but never found a partner (she never settled - she could be the future version of the girl-next-door, having never found anything 'better.')
A minor is like the immigrant who came to this country as a refugee, and has as a result lived a displaced, hard life. It's not uncommon for him to bring up how difficult it had been for him years ago, coming to this country with only twenty dollars in his pocket, establishing himself, starting a business while fretting over relatives still in Germany or Hungary, wherever. I got this image and personality the first time I played A minor as a triad, each note separately. This was after I'd played the sunny-by-contrast D major as a triad. I saw a balding barber, short with an apron, bowing, looking down in front of his shop on the road. This is what he has to deal with, the trials of this life, the hardships, the difficulties. Taking away the immigrant scenario (as A minor isn't specifically an immigrant but a personality) he is the kind of person who is very aware of his disadvantages and very set in them. He knows what he can and can't do. He's very cautious financially. He's accepted that life is this way for him, and he can't change. He knows he's at some sort of disadvantage, but that's his life and he just has to deal with it. As a result he has a very subdued personality. 'Echo Beach' (yes, that song again) in particular uses an A minor chord during the verses. 'Losing my Religion' by R.E.M. uses mostly minor chords, starting each verse in A minor. I don't know who to think of that would match this chord - any refugee in North America from the 20th century maybe? Those who came from difficult childhoods? Maybe my deceased old friend Myles, who decided for himself that he wouldn't have mattered or gone anywhere in life, and ensured that was a reality - though that's a bit of an extreme example.
A major is a shy, seemingly stoic, but deeply caring and meaningful chord, A minor knows his disadvantages and points them out, living them as reality. Either way, they're both good chords, and work well with D major/minor; A major is the dominant chord of D major (A is the fifth note played, completing D major/minor) so it's common in pop music for A to be the next key or note after D. They'd have an awesome relationship, those two personalities, and while I do like D major a lot, my personal focus really seems to on B major/minor - which I'll do tomorrow. I wonder if I should try doing a relationship compatibility chart, as Am would be compatible with Dm & Bm/Bmin. Dm would be compatible with Am, Gm, & Cm. But that's a project for another time.