What name is given to the 86 carat gem housed in Istanbul's Topkapi Palace Museum?

The Spoonmaker's Diamond is an 86 carat (17.2g) pear-shaped diamond in the Imperial Treasury exhibitions at the Topkapi Palace Museum and its most valuable single exhibit. It is considered the fourth largest diamond of its kind in the world. It is not known with any certainty how this diamond came to the Topkapı Palace. The museum's records do list a ring stone called the Spoonmaker's Diamond, which is noted as having already belonged to the 17th century Sultan Mehmet IV. However, this stone, along with its gold, is only 10–12 g (50–60 carats), which is much smaller than the present Spoonmaker's Diamond.

Set in silver, surrounded by a double row of 49 Old-mine cut diamonds (brilliants), it hangs in a glass case on the wall of the third room in Imperial Treasury section of Topkapı's "Conqueror’s Pavilion". These surrounding separate brilliants give it "the appearance of a full moon lighting a bright and shining sky amidst the stars" and are considered to have been commissioned either by Ali Pasha or by Sultan Mahmud II.