This volume results from the 2021 International Obsidian Conference (IOC), a virtual symposium held in the spring of 2021. Originally scheduled as an in-person event at the University of California, Berkeley, the conference transitioned to a virtual venue due to the ongoing COVID-19 pandemic. More than 70 participants from a wide range of time zones stayed up into the wee hours of the night to hear the presentations and engage with others who share a passion for obsidian. Obsidian studies are a robust facet of archaeology, and this volume highlights a diverse range of research themes. Seven chapters in this volume feature studies from across the globe, organized broadly by region, including Europe, Africa, Central America, and South America. A separate section with an additional two chapters presents methodological developments in the field.