I just got 2 beautiful nursing necklaces from Wild Mother Arts, and just had to recommend them!
Here is her site:
http://www.wildmotherarts.com/ and her Etsy shop:
http://www.etsy.com/shop/WildMotherArts?ref=emPineapple agate ($15)

Lapis ($22)

And then she gave me a beautiful freebie, of a peace drop, made of peace jade, for calm and healing <3 I told her I had knee issues and loved the color green, so she picked this out and it is so lovely - a mottled subdued green, white and flecks of purple.
She got everything out super-quick and I love everything about these necklaces, especially how easy to adjust they are and that they distract little fingers while breastfeeding.