Hello buttabdullah99 and cedkugedchgd,
thank you so much for your answers.
I will stop trying for gold by putting diamond x air in the den over and over again. I think i will try diamond x stone just like you, cedkugedchgd. I hope i will get an "angel fail" as well. I don't have all stone-type dragons so i think it's definitely worth a try. Thanks for your help.
But now i have another question about infinity. Because i bread crusader & diamond over and over again but i got another crusader and no infinity. Do you think it was just bad luck that i got crusader and not infinity or do you think that crusader is not as rare as infinity?
If i were you, buttabdullah99, I would try for infinity, with diamond x quetzal, because you can only get forest fails and it is as "easy" as breeding a crusader with fire x diamond. It's such a pity, that quetzal isn't breedable anymore