300, 500, and 800 for those seems like someone has put in an extra 0 into those objectives. these seem way to grindy. excessively grindy for a bounty. a bronze bounty of 300 specific color gems would take someone a few days to chew through compared to some of the others.
Is the bounty objectives getting looked at all for balance? these kind of seem willy-nilly in terms of difficulty. Plenty of objectives to evolve items in a game where item evolution doesnt seem possible.