undermine the premium price still currently charged over synthetic diamonds. However, new technological advances have allowed some independent gem labs such as GIA (Gemological Institute of America) to issue a specific Synthetic Diamond Grading Report which identifies a diamond as laboratory-grown and laser inscribes it with "laboratory grown". Polished diamonds There are several factors contributing to low liquidity of diamonds. One of the main factors is the lack of terminal market. Most commodities have terminal markets, and some form of commodities exchange, clearing house, and central storage facilities. Until recently this did not exist for diamonds. Diamonds are also subject to value added tax in the UK and EU, and sales tax in most other developed countries, therefore reducing their effectiveness as an investment medium. While most diamonds are sold through retail stores at high margin, investment diamonds are usually sold at auctions or privately. Diamonds in larger sizes are rare, and their price is dependent on the individual features of the diamond. Fashion and marketing aspects can also cause fluctuations in price. This makes it difficult to establish a uniform and readily understood pricing system. Martin Rapaport produces the Rapaport Diamond Report, which lists prices for polished diamonds. The Rapaport Diamond Report is relatively expensive to subscribe to and, as such, is not readily available to consumers and investors. Each week, there are matrices of diamond prices for various shapes of brilliant cut diamonds, by colour and clarity within size bands. The price matrix for brilliant cuts alone exceeds 1,400 entries, and even this is achieved only by grouping some grades together. There are considerable price shifts near the edges of the size bands, so a stone may list at $5,500 per carat = $2,695, while a stone of similar quality lists at $7,500 per carat = $3,750. This difference seems surprising, but in reality stones near the top of a size band (or rarer fancy coloured varieties) tend to be uprated slightly. Some of the price jumps are related to marketing and consumer expectations. For example, a buyer expecting a diamond solitaire engagement ring may be unwilling to accept a diamond. There are numerous diamond grading laboratories, with each offering investors, consumers and dealers similar diamond-grading and verification services, including the Gemological Institute of America (GIA) and the CIBJO (Confédération Internationale de la Bijouterie, Joaillerie et Orfèvrerie), also known as the World Jewellery Confederation. If the standards set