My mother was a piano player and piano teacher who gave her last piano lesson ten days before she died. (classical AND jazz-- she played piano in "night clubs" in late Prohibition which I have always taken to be a polite way of saying speakeasy) She started me on piano as one of her students and I took lessons once/week from 6 to 12 (roughly) and I can't now look at a piano book and PLAY it, but I can pick out a melody one note at a time (say, from the Fiddlers Fake Book) slowly, or generally sing a new song out of a book up to speed. I think what Mom gave me was "instinctive harmony" especially on most folk tunes. I can (usually) hear a vocal line and hear what the higher harmony is; if people are singing a duet I can add the baritone harmony. I don't usually stop to visualize, it just IS. If I do visualize, I am thinking of a piano keyboard and see the note played and visualize the entire chord, in whatever inversion it's being played in. I wish I could see those colors and textures, I am envious!