This cuff is formed with two opposite curves - an anticlastic form. In oxidized sterling silver with a 5 mm rose cut black spinel set in 18K rose gold. 

Available in slim, ample or generous profiles. 
Sizes small, medium or large

Widths:
slim: 3/8 - 1/2 inch wide
ample: 3/4 - 1 inch wide
generous: 1 1/4 - 1 3/4 wide