Rolex uses their own in-house gemologists and gem-setters. Gemologists examine and select the gems received, keeping only those that meet Rolex's extremely specific quality criteria. Then the gem-setters place and fix the stones to best reveal the best features of each stone after which the metal is finely carved to precisely hold each stone.The best quality is chosen and each stones height is precisely aligned, along with their position and orientation. Many other details are also included in the process and this is what makes each Rolex bezel top quality.