This beautiful solitaire engagement ring features a sparkling 0.50 carat old European cut diamond of H color and VS2 clarity. The gem is set in platinum prong mounting with carved scrollwork detailing on the shoulders. The inside of the setting is stamped with the maker’s mark "B.S. & F." for Black, Starr & Frost, an important an important New York City jewelry firm. This ring dates to the early twentieth century, c. 1920, and is in excellent vintage condition. It is presently a US size 5.5, and can be re-sized upon request.