]Is it proper or improper to wear a pin on a suit as well as a necklace?

I would only wear small pearls at the neck with a pin on the suit.

As long as neither piece is too loud or attention-grabbing, I see no reason you can't wear both. In other words, don't wear a pin the size of your palm and a necklace that is big and clunky. If you are unsure, pick one over the other.

]Is it proper or improper to wear a pin on a suit as well as a necklace?

Choose a simple looking necklace and pin if you wish to go for both, else it would probably look "over-accessorised" !

PLEASE - I realize you want to answer as many questions as you can about jewelry but this is (also) two years old.