Liberia intends to harness the development potential of artisanal mining through formalization. However, there are several obstacles that the country needs to overcome for it to succeed. The existing literature provides evidence on the challenges faced by miners and local authorities, but fails to make a distinction between different types of activities. This study sets out to identify differences in formalization patterns across the two largest artisanal sectors, namely gold and diamond mining. Drawing on an extensive survey of 231 communities and 174 mines in Gbarpolu County, we spatially match mining sites to their nearest license recorded in the country’s cadastre. To do so, we consider both distance to licenses and concentration of mines around titles before loosening the definition of formality by exploring town chiefs’ perceptions. We complement our spatial analysis with qualitative insights into miners’ views on the challenges and opportunities of artisanal gold versus diamond mining. Our findings show that artisanal diamond mines are more likely to fall under what we define as an “umbrella of formality” compared to gold mines. We explain this difference through geology, but also the history and perceptions of the respective minerals. Against this backdrop, we question the effectiveness of formalization as it is currently conceived in Liberia. We argue that distinguishing between artisanal mining sectors is important to understand the different sets of incentives and constraints that miners face. This, in turn, is key to the design of tailored and effective formalization policies.