These are some of the clearest images of the thistle brooch ever. Many thanks Isabelle D!

I wonder if, when the contractors who built Kelvin Hall, Glasgow presented their gift to Queen Mary in 1927, they ever envisaged that this brooch would be worn by a monarch to a Scottish parliament?

The other thing which intrigues me is why it was not seen in public for such a long time? Did Queen Mary perhaps leave it to QEQM who preferred to wear her own thistle brooch? Or is it that perhaps QEII had the jewel all along but has only commenced wearing it in public in recent years? We know that is the case with some other large brooches she possesses.