I hate what mining does to our world (both in terms of precious metal and gems and both in terms of the environment and the human rights issues).
I'd say to hell with rings, but I like the symbolism, and I like being transparent about important aspects of my identity.
I'd go vintage except that most of the styles I've seen are very ornate.
My number one contender right now is a ring from Brilliant Earth. They use recycled metal, and they've said they would put in a fake diamond (moissanite) for me. It's created in a lab. Then if people lean over to ogle my diamond, I could stand on my soapbox and say it's synthetic because the diamond trade disgusts me.