This quality Art Deco Diamond Trilogy ring, dating to the 1920s features three very lively diamonds, set in Platinum and 18ct White Gold.   

The  diamonds have an estimated total diamond weight of 0.35ct  (0.15 x 0.10 x 0.10) and as you can see in the video, they are extremely lively when the light hits them.
It is currently a UK size P 1/2, which is a USA size 7 3/4, but it could be re-sized within reason.  It weighs 2.81g and is marked for 18ct Gold and Platinum.  

This classic ring, which would be a wonderful choice for an engagement ring,  has been lightly cleaned and is ready to wear!

Three stone rings are known as Trilogy rings. Trilogy rings represent a commitment to the past, present and future, and they were often given as a token of love, and are frequently worn as engagement rings.