It seems a long time ago that I answered this one but I spent a lot of time googling Rio Tinto and they had a change of name/merger and I think it was during those years that they were Rio Tinto Zinc. You can google to get the detail.
Well not really. I don't remember the exact detail but if their name was just Rio Tinto then it wouldn't have given you the RTZ that you needed for the answer. You needed the period when their name was Rio Tinto Zinc so you could get to quartz.
I wasn't going to ask but my last one has been driving me mad. Can you give me any clue to No.38 about the First Listener and the last pluck. I'll be able to have a good Christmas if this one is sorted.
I'll have to think about that while I'm making the fruit salad,
Blake set Ringo is an anagram of a very popular TV character (American) whose series ran for ages - still turns up on BBC 2 sometimes. Set in the army!!! In 1996 there was a film of this character and the lead actor is the answer you want. Hope this helps.