Mystery setting
Serti mystérieux | ミステリー・セッティング | 神秘镶嵌法
Mystery setting
A groove is cut into a baguette stone and the stone snapped into a metal rail. The stones are set tightly together so that none of the metal is visible.
This technique was patented in 1933 as a "means of mounting precious stones" by Van Cleef & Arpels which registered "mystery setting" as a trade name in 1936.