1930's Cluster Diamond Engagement Ring in Platinum1930s Cluster Diamond Engagement Ring in Platinum. This fabulous Art Deco engagement ring features . 93 carats of Old European and single cut diamonds set in platinum. The glamorous mounting is gently stepped upwards from the shank, and each step bordered with fine milgrain detail around the single cut diamonds. This design creates a roughly domed profile from the side view and this makes the ring far less cumbersome to wear.