Gemos Gems is one of the ten sightholders listed by TanzaniteOne, which operates in a manner similar to the De Beers supplier of choice system. For Gemos Gems, the fixed-price rough lots from TanzaniteOne are well graded, sorted, and organized, making it easy to calculate costs and profit margins. The company also buys an equivalent amount of rough on the open market from other miners and dealers in Tanzania. The rough supplied by Arusha’s independent dealers has become very well graded, as opposed to the mixed lots and mine runs they supplied several years ago.