Sterling Silver Smokey Topaz Stone Ring

Sterling silver has "950" engraved on it for proof. "750" is also engraved which means 18K gold jewelry because the metal is made of 750 parts per 1,000 of pure gold. Has a brown square stone in the middle. We believe it is an older Lagos ring, but are not entirely sure what brand. It's a very valuable ring, but no specific markings because it has been rubbed off. Other than that the ring is in great condition, it just has some wear to the outside metal.