It is a very beautiful tiara. Unfortunately, I haven't seen any of the previous Countesses of Bradford photographed wearing tiaras or the previous Ladies Newport.
A few news reports from early in the 20th century said that the Countess of Bardford had some magnificent jewels -- but didn't provide photos!!
At the time the Countess of Bradford was a Lady in Waiting in Queen Mary's Household, and as usual for such ladies photos of them in grand jewels are scarce.