Since we can already get ascended jewelry outside of the trade skill why not let jewel crafters create ascended sigils, runes, inscriptions and infusions. I haven’t thought though all the details but you would start with an exotic rune/sigil and end with an ascended faceted rune or encrusted sigil. The names would be like Ruby Faceted Rune of the Adventurer and Emerald Encrusted Sigil of Might.
Maybe we can use low level runes and sigils as crafting materials. Faceted Runes will have a seventh effect. Encrusted Sigils might have additional stats or procs depending on the gems used. Not sure how inscriptions and infusions would work but the the big idea is that Jewelers would be masters of upgrades.
