Ring

Design and Finishing:
Central Stone:
The prominent feature is a large, rectangular emerald-cut black onyx, known for its deep, opaque black color.
Halo Setting:
The central stone is encircled by a "halo" of smaller, round, brilliant-cut stones, which enhance its size and sparkle.
Band Design:
The band appears to be relatively slender, possibly with additional smaller stones extending down the sides, contributing to a more elaborate design.