semi-mount:https://www.doveggs-seattle.com/products/doveggs-split-shank-double-halo-engagement-ring-engagement-ring-only-semi-mount-onlyexclusively-to-doveggs-stones?_pos=3&_psq=split+shank+double+&_ss=e&_v=1.0
center stone: 0.5ct round lab created stone
material: sterling silver 925 with platinum plated
ring size: US size 9