This Insight analyses how different economic policies, peace, leadership and laws can lead to starkly different minerals-sector driven developmental outcomes even in countries that are very similar. For the case studies selected for this Insight, there are observed similar characteristics with respect to: geomorphology; geology; culture; population groupings; colonial and post-colonial history; and the recent and/or current existence of violent conflict. The experiences of two neighbouring east African countries, Burundi and Rwanda, were analysed and contrasted, as informed through a detailed review of available evidence. The results indicate that Rwanda has significantly increased the income, production and development outcomes derived from its mining sector compared to Burundi. Suggested causes for this divergence are identified and discussed below, notably: the importance of peace/stability; the protection of property rights; the absence of an authoritarian State; the developmental policies of the State with respect to mining-led economic growth (dirigisme); and the role and importance of the private sector and competition. Key words: Burundi, Rwanda, mining, war, political security, policy, regulation and laws.