Some of these were used to make rare blue diamond engagement rings like the French blue, while others were stolen or recovered later in other parts of the world. Below is a look at two such diamonds.           The French Blue Diamond In 1668, a 115 carat Tavernier blue diamond was bought and cut into the French Blue under orders of King Louis the Fourteenth. Later, the French Blue was used on several occasions in the royal court. Later, the special diamond was handed over to Marie Antoinette. A long-time after this, in 1791, the French Blue was transferred to the government. The Hope Diamond During the Revolution that followed the 1790’s, the French Blue was stolen. Many years later, a brilliant blue diamond with stunning opulence was found in the possession of a London diamond Merchant. There are many speculations that this diamond was cut from the French Blue.