I've got a couple of wisps of information floating around my head which could do with the ballast of genuine facts.

Firstly, I recall reading that typical white gold needs coating (with what? rhodium?) to prevent it tarnishing; however I believe I also heard that a stable white gold alloy has been produced. Who might be using that, I've no idea.

Secondly, I think I recall reading that rose gold degrades in the very long term (does explain the development of Everose?) To what degree does this happen? Anyone got photos of fifty year old RG?

Thirdly, are there any ageing issues with 18k yellow gold?