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Well done, JJ. You get gold, Danny gets the silver & emmie gets an honourable mention for a good & very fast try. (I thought at first that there were no 8-letter clues, but found them a wee bit later.)
Emerald fits well. There's only one place for it to go, although there is a second possibility, which can be quickly rejected. The rest of the puzzle works out quite easily, although what I thought might be a G turned out to be an X. There are also very few Ns.