Dave's query below prompted me to look at what information I have about Queen Alexandra wearing Queen Victoria's small diamond crown.
Perhaps the most important thing to establish is that Queen Victoria left this as a personal jewel to Queen Alexandra and, so after the death of Edward VII, she was able to keep this for her own personal use.
There is evidence (primarily from Pope-Hennessy's biography of Queen Mary) that there was a dispute between Queen Alexandra and Queen Mary as to who should wear certain jewels.
Queen Mary won the battle over Queen Victoria's Regal Circlet and wore it to the first Opening of Parliament by George V.
As the small diamond crown was left personally to Queen Alexandra she won that battle, and to ensure her rights were known the information was leaked to the press which widely reported the matter. For example the item published by
The Times Queen Alexandra seems to have been particularly fond of the small diamond crown, wearing it either alone or behind another tiara.
She wore it each year, alone, for the Opening of Parliament, commencing with the First Opening.
And the last in 1910.
The Queen wore it for the first Court held by herself and Edward VII, though there is some discrepancy in the press reports as to whether she wore it alone or behind another tiara and this is reflected in the sketches in the press.
The Times, which may have had a press release from the palace stated:
Some of the illustrations in the press.
Press reports show that Queen Alexandra wore the small diamond crown frequently either inside the Regal Circlet or behind the amethyst tiara and her also her Kokoshnik tiara given to her by ladies of society for her silver wedding anniversary. I haven't seen reports that she wore the small diamond crown inside the Diamond Diadem (the one worn by QEII on her way to Open Parliament).
The Regal Circlet seems to have been Queen Alexandra's choice for use with the small crown. After she lost use of the Regal Circlet as we know from Hugh Roberts she commissioned her own version of that jewel and continued to wear it with the small diamond crown on both official state occasions and for more private, family functions.
As the Queen Mother, Queen Alexandra did not attend many Court functions, but she was present on select occasions -- for example the Danish State Visit in 1914.
Danish State visit - Opera gala preformance.
Even for family occasions Queen Alexandra would wear her regal circlet with the small diamond crown, as she did for the wedding of her granddaughter, the Duchess of Fife to Prince Arthur of Connaught in 1913. This occasion has resulted in some of the most memorable images of the Queen.
But the most famous image of Queen Alexandra wearing the small diamond crown is perhaps Francois Flameng's 1908 painting.