Russia: Royalty & the Romanovs
Siberian Amethyst diamond brooch pendant made by Fabergé | Romanov Jewels| Imperial Present of the Czar.

In August 1909, Tsar Nicholas II and his family made their last visit to England. They attended the annual regatta at Cowes on the Isle of Wight, and the royal families dined together on each other’s yachts. A local photographer was commissioned to record the occasion and produced a double portrait of the Prince of Wales (later King George V) and his cousin Emperor Nicholas, which shows the strong family resemblance.
During the visit the Princess of Wales (later Queen Mary) was given a jewel as present, see above in the picture, a diamond-set Fabergé brooch made from a Siberian amethyst, a stone famous for its intense purple hue.
More details and impressions of the the Czars visit in 1909 at Cowes click

This and other  imperial gifts and  royal presents are on display at

Russia: Royalty & the Romanovs
The Queen’s Gallery, Buckingham Palace 9 November 2018 – 28 April 2019