En tremblant-Flower Bouquet of Gemstones

This magnificent gem, probably from the 19th century, was given to the museum on permanent loan by a stroke of good fortune.
Historians and some experts of the Hermitage in St. Petersburg have two assumptions about its origin.
The first, though less likely, is that several of these bouquets were made - personally commissioned by the Russian Empress Elizaveta Petrovna, mother-in-law of Catherine the Great, to be worn as corsage on grand occasions. Most of the empress's jewellery was made in the 1750s, and this trembling brooch could be one of them.
The second and more likely assumption is that the ancestors of the present owners must have seen the brooch at the Treasury of the Hermitage in St. Petersburg, housed in the Winter Palace, where the jewels of the early empresses were kept and some of them were exhibited until the revolution of 1917. Very few people had access to this treasury. Carl Fabergé (1866-71) worked there voluntarily as a young man and was very familiar with the objects. The ancestors of the present owners, fascinated by the brooch in question, commissioned him to rework a similar one.

Further information from the owner:
This rare and magnificent gem from the 19th century came to the museum on permanent loan by a stroke of good fortune.
Its story begins with a family of horse traders whose journeys took them across the Russian Empire in the mid-1800s. As they traded their prized horses, they gained access to the circles of Russian aristocracy.
The Brooch’s origin captivated historians and experts at the Hermitage Museum in St. Petersburg, leading to two theories:
The first believes that several of these bouquets were personally commissioned by the Russian Empress Elizaveta Petrovna, mother-in-law of Catherine the Great, to be worn as corsages on grand occasions. Most of the Empress's jewelry was crafted in the 1750s, and this En Tremblant Brooch could be one of those pieces.
The second theory proposes that the ancestors of the current owners, having seen the Le Grand Bouquet Brooch at the Hermitage Treasury in the Winter Palace’s secret vaults, were so fascinated by it that they commissioned Carl Fabergé to craft a similar one. The royal jewels were hidden in these vaults until the Revolution of 1917, and only a select few had access to them. Fabergé, who worked at the Hermitage as a young man (1866-71), was highly familiar with these treasures.