In 1980, the 112.53 carats weighing Mouna diamond was earthed in South Africa. The name of the stone is derived from its former owner, Mouna Ayoub, wife of Saudi Arabian businessman, who was also an advisor of king Fahd of Saudi Arabia. Unfortunately, the information such as its date of discovery and mine of origin is unknown.

Features of the stone :

The diamond is an intense fancy yellow, cushion cut, VS-1 clarity grade stone, weighing 112.53 carats. The Gemological Institute of America (G.I.A) reported that it was the largest fancy yellow diamond ever rated by them. Being a fancy yellow colored, it was categorized as type II diamonds, which consists of trace amount of nitrogen impurities. The scattered nitrogen atom produces vacancies in the cubic lattice structure and these vacant empty spaces absorb the visible light from the spectrum, resulting in fancy vivid yellow color. It is a plastically deformed crystal. The most exquisite feature of the stone is that it emits strong fluorescence when exposed to ultraviolet light and light fluorescence with artificial or normal day light. The facets of the stone are elegantly crafted by skillful master cutters and laser sawing technique is employed to eliminate the inclusions.

History of the diamond :

The massive diamond was believed to be earthed in South Africa; however, there is no evidence for this. Later the stone found its way to Mouna Ayoub, a Lebanese Christian, wife of Saudi-Arabian businessman. She migrated to France after her divorce and sold the sparkling wonder to Christie's, who mounted the valuable stone in a Bulgarian pendant and put it up for an auction, in Geneva. The stone was purchased for a record breaking price of $ 3.2 million by an anonymous diamond collector, in 1998. The stone still remains with the anonymous diamond connoisseur and collector.