Stuart Sapphire The Stuart Sapphire June 2, 2024 sensualsapphires The British Royals have had a longstanding association with blue sapphires but the Stuart Sapphire is one of the most important as it is set in the Imperial State Crown of Britain. The cabochon-cut sapphire weighing 104 carats was acquired by the Queen’s ancestors in the 14th century. While the history of its acquisition is quite muddled it was probably unearthed in Asia.