Priscilla Annesley, Countess Annesley wears a tall diamond tiara in a portrait published in The Sketch, May 1902; the tiara, appropriately for the time, appears to be an example of belle epoque design

Theresa Vane-Tempest-Stewart, Marchioness of Londonderry wears the family’s diamond tiara in a portrait taken around the time of her marriage in 1875; more on the tiara over here!

Vivien FitzGerald, Duchess of Leinster — fourth wife of the 7th Duke of Leinster — wears a tiara and necklace as she travels to the State Opening of Parliament in London, November 1975; I don’t have any additional information about the jewels