Incomparable diamond is a rough African diamond weighing 890 carats. It is a largest found diamond in the world at MIBA diamond mine, the democratic republic of Congo in 1980s. A young girl playing in the pile of rubble outside her uncle’s house found the diamond.

The girl uncle sold the diamond to the local African diamond dealer who in turn sold to a group of Lebanese buyers operating out of Kinshasa. Later, it was purchased by Antwerp, the senior de beers buyer. After sometimes, de beers sold to Zale Corporation. The stone was unveiled on November 1984 and that day was celebrated as the seventy fifth anniversary of Zale Corporation. Shortly, it was displayed on natural history wing of Smithsonian institute. Mr. Samuel was the cutter for the precious incomparable diamond.

The work of the stone was started on the 14 fragments. Mr. John Sampson white, curator of mineralogy at Smithsonian examined the leftovers and found the variation of color in each fragments. As a 890 carat uncut stone, no difference can be found by him, but some of the fragments were in rich yellow with slight brown overtones like a Smokey amber and others were pale yellow and the rest were nearly colorless. From the fragments, fourteen gems were cut and the largest being kite shape of 15.66 carats. The others were of varying shapes weighed 6.01, 5.28, 4.33, 3.45, 3.32, 3.31, two weighing 2.74, 1.99, 1.74, 1.63, 1.52, and 1.33 carats.

The biggest piece of the gem weighing 407.48 carats, it is the third largest diamond. The Gem Trade Laboratory Incorporated the diamond as Shield-Shaped Step Cut, Internally Flawless clarity and Fancy Brownish-Yellow in color. Its unusual triangular shape extracts a new term from Marvin Samuels - a ""triolette."" The incomparable diamond was graded by GIA as internally flawless in 1988. On November 1984, the finished stone were put on display as a single golden diamond of 407.48 carats (81.50 g) in 'triolette' shape along with additional fourteen gems.