In a world where you can create even the money without being able to distinguish the fake money from real money I fear there will be no longer any value, you can just get what you want, the only "money" it is probably waiting our turn to a "printing machine", if the machine print itself then also there will be no longer any turn.

Probably people will be so stupid to create "new values" (the only valuable thing would be wisdom so I fear there will be an economy based on wisdom and knowledge where the only form of payment is "teaching stuff".)

Assuming engineers find a way to just create jewels (and no other object) so that we can still have money and value:

>  in a world where jewelry is no longer motivated by scarcity, what new factors would determine what kind of jewelry people wore, since everyone could make or acquire at low cost any sort of design made of any material. 

Probably people will just have to create their own jewels just to look pretty. I think it will just become similar to how we choose which posters hang in our home, probably there will be custom jewel designers that helps you creating jewels and you pay them for their time, right know there exists street artist that create temporary tattoos, I think the jewel tendency will become similar to that.