Hi tvbteam,
1. There are some cases where jewelry is printed with silver, but I don't have enough info on this.
2. Usually jewelry is printed with Sculpteo Silver Brass, but some services can provide gold if needed.
3. If you need to find a designer, you can go to our 3D jobs and request assistance for your projects. The link is: https://www.cgtrader.com/jobs
Hope this helps.
All the best,
Eduardas