Vermeil (black onyx?) ring

Original price was: $40.00.Current price is: $24.00.

This is a vermeil (sterling) and what I believe is black onyx ring in good pre-owned condition. It is marked STERLING and a symbol but the lettering is worn. The ring shows little to no wear on the outside. It is about a size 6 3/4. The stone does test as real but I’m unsure of what exactly it is, though I do believe it is onyx.
Cleaning and or polishing may be required. As is, no returns.