Men's gold ring set with a square-cut red stone, likely synthetic ruby or garnet, accented by a trio of small diamonds (not tested), set diagonally on one shoulder. The interior band shows a hallmark indicating "10K," signifying 10-karat gold construction. The design is bold, with a flat-top setting and substantial band width.
The condition appears good, showing light wear consistent with age, and the original vintage box is included. No specific maker's marks or additional provenance are visible. See photos for measurements, if taken.