Welcome to the worst grind in the game... briar jewelry. Ugh.

I use this on two stam characters. It comes from the world boss dailies you get at the inn near the guild traders in orsinium. Also, the delve dailies from the orc stronghold in the central north area. Also, treasure chests from treasure maps.

Here's the rub. My buddy and I ground our CPs by running wrothgsr world bosses. On weekends, we'd run six dailies on a character, then switch to another. We tended to run 20 dailies like this for the xp. A year into this, plus playing delve dailies and doing MANY chests, I barely have two good jewelry sets...some pieces are still healthy, I think. I have easily opened 2,000 wrothgar daily chests. Yes, the briar robust jewelry is that rare.

Now that briar is sold in guild stores, I promise that it will be faster and less infuriating to go spend your time earning rare/expensive motif chapters. Sells these in a guild store and raise the gold to just buy the dang stuff.