What are the data sources used to create and maintain this index?

Core pricing data is collected from a group of fancy color diamond experts that trade a significant volume of rare fancy color diamonds, based in three diamond trading centers: Hong Kong, New York and Tel Aviv. Each index data set is based on diamonds traded and evaluated during each six month time period. As of January 2015 and going forward, data will be evaluated over a three month time period. Information shared by the parties is verified and compiled by The Fancy Color Research Foundation. Separately, the prevalence data necessary for weighting the different price data points in order to reach a composite index, was developed by an independent consulting firm which conducted an in-depth research of the fancy color diamond sources and availability.