Zendae (atys)
You can find at least one weapon mission everywhere. At least one armor mission. At least one ranged mission. One thing about jewel missions is that you can find one with every overseer, in all cities and all tribes over atys. And it's always the first mission, you don't have to search in the list.
It's more difficult to find a mission for swords, for example.
Sure, jewels are a bit easier because there are only 6 plans for them, and you only use basic quality, so you can start making money earlier.
In the long run however, I think those crafting other gear at medium / high quality will get richer.
Zendae (atys)
So you can dig your mats, then travel to many overseers and work for them. You have plenty of choice.
Some mission ask only for 1 or 2 jewels which does not worth it, but others for more than 10.
Nonetheless, most overseers request 5 jewels or less. Even 10 basic quality jewels use 30 materials, which is less than one high quality (skin 3) heavy armor piece.
Plus, everything else equal : a weapons crafter traveling to all tribe overseers will still make more money than a jeweler doing the same.
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