UPDATE: by total coincidence, Ideal Bite covered diamonds today. We get it by email and we do not know how to link to it, but here is a link to their blog.
About Gold mining: "There is often little regard for the environment during gold mining, and all too often, the spoils of the process continue to poison the environment long after commercial operations have ceased." About diamonds: "diamond mining isn't sustainable. Even if we are able to make progress with regard to the social cost of diamonds, the Earth doesn't yield up her natural diamonds without an environmental price."
About Diamond mining: "Perhaps no aspect of our modern culture leaves us more conflicted than the positive symbolism of diamonds, in contrast to the suffering and environmental destruction those diamonds carry as their legacy."
The New northern Canadian mines do not get a free pass- "Loss of fish habitat through draining of lakes, destruction of streams, changes in water quality. Water quality changes are measurable as far as 200 km downstream of Lac de Gras (Ekati mine), and there have been irreversible changes to water quality and possibly species composition in Snap Lake (De Beers diamond project). Twenty lakes have been eliminated altogether, with no fish habitat compensation measures in place."
Lots of information; lots of nice rings; a bit light on the romance and the fabulous deBeers marketing but if you want a truly green ring (they even sell carbon offsets for the energy used to smelt the metal)go to ::greenkarat