The Wittelsbach Diamond, which has been in the Wittelsbach family since 1722, is expected to beat the world auction record set by a 13.39 carat blue diamond that gathered 8.9 million dollars at Christie's Geneva in May this year.
The greyish-blue sparkler, which has been a part of a private collection since 1964, has been traced back to as early as the 17th century after it had been originated in the Indian diamond mines.
"Blue diamonds are rare and to offer a blue diamond of this size, quality, shape and provenance is truly extraordinary," the Telegraph quoted a spokeswoman as saying.
The coloured diamond, sought after by European rulers for hundreds of years, has appeared in the international market for the first time in almost 80 years. (ANI)