About jewelry sites--here are two that I feel fairly comfortable about passing on to the audience:
www.greenKarat.com
www.ice.com
We got our wedding rings from Green Karat (I sent them some of my old gold and silver jewelry (broken pieces, etc.) which got us a discount), and their service was quite good. Ice.com I only know by reputation from the Budget Fasionista (book and website), but the prices certainly look good.
If you are looking for fully natural gemstones then Greekkarat does not have those. They are more into the enviro conscious synthetic mineral stones (lab created). However, the pricing is good because of this reason. As for metal, recycled metal is good as newly mined metal so you have a safe bet getting bands etc from GreenKarat.
Among other online websites for jewelry, www.Bluenile.com is a well established website for diamonds and they do supply the diamonds with a certificate.
Happy Shopping
