History of Famous Jewels and Collections: Re: QEQM. Franck's photo. What was worn on the hat?

Franck posted this photo.

It shows the King and Queen on the steps of St Paul's, London on 1 October 1939 after the service for the National Day of Prayer.

Queen Elizabeth the Queen Mother wore the same hat and outfit at least 4 times during the same summer/autumn in 1939.

I will show these below and clearly identify each occurrence so people can refer to that when commenting.

1. National Day of Prayer. I October 1939

Enlarged detail from photo above.

View of hat from the Illustrated London News 7 October 1939

View of hat from Sphere 7 October 1939

2. Return to England following the north American tour. Return date was 22 June 1939 .

Arrival

This has the best detail of any photo.

In London on day of arrival.

3. On the way to Crathie Church 1939

4. At Dartmouth Naval College 1939

I suspect that what we can see is an ornament, not a jewel, on HM's hat, and that it is the same in all the photos.

When I looked at the last photo I had no doubt that the ornamentation was the same as the one seen as HM walked down the gangway on her return to England.