Bridesmaid gifts - jewelry? - help!

I'm thinking of getting my girls necklaces to wear to the wedding...since it's really the piece of jewelry that shows the most, that way there's less chance of them looking way off...and I think it's a nice gift and remembrance.

I'm having trouble finding something simple and classic that fits all of their styles. I want white gold or silver, something with a little sparkle - maybe diamonds or crystals.

My girls will be in navy - so I though sapphires might be a nice way to go too. ...or maybe a pearl pendant?

What do you think of these two pix? I think I'm leaning away from the sapphire one.