Before we analyze the options available to diamond jewelry retailers to resolve their long-term supply dilemma, consider again the structure of the value chain that supplies gem-quality stones to retailers. In contrast to the concentration of the upstream segment, which is dominated by a handful of mining companies, the middle and downstream segments of the diamond value chain are highly fragmented, with more than 200,000 retail players, 10,000 jewelry manufacturing companies, and 5,000 cutting and polishing companies. The top miners account for about 85% of all rough production by value, and up to 110 long-term contract holders and sight holders, most of which are vertically integrated to a greater or lesser degree, control more than 70% of that supply by value