Request: Lab Gem Custom Jewelry Repair

My spouse lost the main gem in her diamond engagement ring and we would like to have it replaced. We were also considering some upgrades like having it soldered it to her wedding band (missing one pave stone) and perhaps adding stones for our children.

Honestly we have something fairly specific in mind but are realistic regarding our budget and expectations.

Prefer SW side up to the Galleria location. Also only really interested in lab-grown gems for budget and ethical reasons.