Can't clear quest

I believe the condition likely refers to the Gem obtainable within the game app, not the gems you get from playio. Based on other posts, it seems like the Gem is the item that looks like a light blue jewel. If you clear them before finishing the game, you should be able to obtain them upon completion, but what do you think?

Even after obtaining 550 gems in the game, the reward isn't given for some reason, so I've already quit.

It says in the game that it's displayed when you clear it, but the wording was strange, possibly due to translation, so I initially skipped it. I can't confirm it otherwise.