The article shows how the 2006 discovery of significant deposits of diamonds in eastern Zimbabwe transformed the minerals sector and its nascent regional business networks, with significant political implications. It argues that diamond revenues have been used to prop up the ruling Zimbabwe African National Union – Patriotic Front (ZANU-PF) party and maintain its hold on the state and dominance in the Government of National Unity. Internal battles over control of and access to diamonds posed a direct challenge to the viability of the new, ‘power-sharing’ unity government and prospects for a democratic transition in Zimbabwe. Because profits from mining are benefiting security forces and factions of the ZANU-PF elite, Zimbabwe's diamonds have cemented political corruption, further marginalised the two opposition parties, and may have guaranteed election victory for ZANU-PF in the country's next election.