1920s Art Deco 1.90ct Old European Cut Diamond (GIA: I/SI2) Ring
Platinum, Old Marquise & Single Cut Diamond Sides (sold)

Probably one of the loveliest (and definitely one of the most valuable) rings we’ve ever had.  The center diamond is nearly 2 carats and beautifully cut.  

This style of mount was popular in the 1930s, and we’ve had several of similar design before.  But usually there are round cut diamonds set within each of the little leaf shapes, rather than actual marquise cuts, which were very rare in the 1920s and 30s.  With the early marquise cuts, and the excellent craftsmanship, I’m quite sure the ring predates the ones that you typically see from the 1930s.  This is early Art Deco, with very forward thinking design.