OK, do you have ANY background in basic art lessons at all? Do you remember Warm Colours and Cool Colours? Basically, people's skin and hair can be Warm, Neutral, or Cool cloured. If your girlfriend has Brown, Yellow blonde, or Red hair, and warm, maybe tanned skin that is quite yellowy in it's shadows, (so her skin is creamy, beige and yellowy) then she'll look a lot better in yellow Gold jewellry than in silver...even though you have had yellow gold jewellry ruined for you by "Bling" connotations.
If she has dark black hair, or mousy coloured hair, or silvery or white blonde hair, and pale skin that has blue tones to it in it's shadows, so her skin is much more pink and white and blue, rather than beige and cream and yellow, and maybe she'll have rather pure green or blue eyes, then silver or white gold will look good on her.
Personally I like the second pendant (It looks like a Yin-Yang sign to me) a LOT better than the first one.
Firstly, that heart shape is very common, I see it around a lot. I don't want to be wearing identical jewelery to everyone else.
Secondly, the lop-sided heart shape in itself annoys me for some reason, I dont' know why.
Thirdly, Yin-Yang signs have a LOT of philosophical and cultural significance for me. I like having them around me.
Fourthly, I've never seen a Yin-Yang sign done like that. It's a unique treatment of it as far as I've come across before.
I don't know if I've been at all helpful, all those last points have to do with MY personal tastes, and we aren't talking about me.
