Edward Jay Epstein:
The diamond invention—the creation of the idea that diamonds are rare and valuable, and are essential signs of esteem—is a relatively recent development in the history of the diamond trade. Until the late nineteenth century, diamonds were found only in a few riverbeds in India and in the jungles of Brazil, and the entire world production of gem diamonds amounted to a few pounds a year. In 1870, however, huge diamond mines were discovered near the Orange River, in South Africa, where diamonds were soon being scooped out by the ton. Suddenly, the market was deluged with diamonds. The British financiers who had organized the South African mines quickly realized that their investment was endangered; diamonds had little intrinsic value—and their price depended almost entirely on their scarcity. The financiers feared that when new mines were developed in South Africa, diamonds would become at best only semiprecious gems.