In a newly published historical novel, "The French Blue", gemologist and historian Richard W. Wise proposed that the patent of nobility granted Tavernier by Louis XIV was a part of the payment for the Tavernier Blue. According to the theory, during that period Colbert, the King's Finance Minister, regularly sold offices and noble titles for cash, and an outright patent of nobility, according to Wise, was worth approximately 500,000 livres making a total of 720,000 livres, a price about half Tavernier's estimate of the gem's true value. There has been some controversy regarding the actual weight of the stone; Morel believed that the 112 carats stated in Tavernier's invoice would be in old French carats, thus 115.28 metric carats.