Analysis of Effect of 4C Grading on the Price of Small-Carat-Weight Fancy Yellow Diamond

Over the past decade years, the coloured diamond market has became more and more fiery, and the price has been gradually increasing. However, it is not very clear of variation law of the market price since its rarity and other factors. So far, the coloured diamond price system has not been established as mature as colourless diamond, and few researches reported the price of coloured diamonds at home and abroad. Therefore, studying the influential factors of coloured diamond price is very important. The authors analyzed the price of the total 1 031 fancy yellow diamonds of cushion cutting in global markets, especially the price of diamonds with weight varying from 0.20-0.91 ct, which was provided by a mid-large diamond wholesale company. It is found that there is a linear relationship between 4C (including carat, clarity, cut, colour) and price of fancy yellow diamond respectively. The carat weight has positive linearity with carat price, and colour also influences a lot on it, while cutting impacts a little to its price. Additionally, ratio of cutting grade difference of fancy yellow diamond with small carat weight and its price has been quantified. Through horizontal comparison, premium was dependent on clarity, colour and cut grade difference as well as the price and the price growth rate of fancy yellow diamond.