Knowing where to look makes all the difference, and picking a zone that is somewhat active.
A quick run around Stonefalls (takes me about 20 minutes to circle the zone... I'm built for speed atm. Gathering speed CP helps, too.), netted me a little above 100 in both Pewter and Silver dust.
There were enough players in the zone that nodes are harvested, spawning in seams in their places, without there being so many that everything feels scarce. Summerset and the starter islands are currently so full of people during prime times that its almost pointless to try farming there.
Jewelry drops aren't scarce, either, depending on how you go about it. If you're just killing mobs, sure, or even doing dolmen runs.
Treasure chests seem to be giving more green and blue jewelry drops than before Summerset hit, and Summerset containers and Vvardenfell urns? They drop loooots and looots of white jewelry, scaled to your CP. I'm at 40 Jewelcrafting without having bought anything to level it, plus whatever exp JC writs give. I'm not even really working on it, either - I'm hitting up those same things for recipes, and for things to sell on the guild traders.