The commercial exploitation of Sierra Leonean diamonds began in the early 1930s, in the Kono District in the east of the country. The first discoveries had been made by a British-held concern called Consolidated African Selection Trust, or CAST, in which a British shareholder body, Selection Trust Limited, shared a significant interest with the diamond giant, De Beers. Transparency, of course, was not by any means absolute, but under British colonial oversight, the movement of diamonds out of the country was regulated and royalties channeled reasonably appropriately.

In the past, all diamond mining in Sierra Leone had fallen under the control of the Sierra Leone Selection Trust - or SLST - a private investor body with exclusive rights to mine diamonds in Sierra Leone. By the mid-1950s and 1960s, illegal and illicit mining had taken over large areas of production. Figures vary, but by the 1960s, one can assume a figure of upwards of 100,000 illegal miners, both domestic and foreign, were active in the Kono District. Armed groups began to appear, challenging private SLST security, eventually fermenting a situation of anarchy under which regulated and taxed diamond production diminished to a trickle.

Naturally, the corruption was at its most pervasive and creative surrounding diamonds. The industry was effectively criminalized, becoming the basis of a patrimonial shadow system geared toward sustaining wealth and power at its center. Distrustful of his own countrymen and tribal opponents, Stevens handed off much of the day-to-day business of diamonds to Lebanese businessmen who had been a somewhat anomalous presence in Sierra Leone since the end of the 19th century. From a peak of over two million carats officially exported in 1970, legitimate diamond exports dropped to 595,000 carats in 1980 and 48,000 carats in 1988.