Hi John,
I think you can check out some online boutiques offering quality jewelries. My friend Kate just got married last year and I gifted her suuuuch a gorgeous necklace from the designer label, Ginger and Smart ( http://www.gingerandsmart.com/shop/objects/jewellery.html ) I guess you can check it out or maybe some other stores offering quality jewelries. I so love these ideas from Pinterest too- https://www.pinterest.com/explore/sentimental-wedding-gifts/ !
Cheers!