Hand-carved arrowheads and jagged spears made of obsidian, a sharp rock formed by volcanic magma, are remnants of vast prehistoric trade networks that once cut across western North America.

Master carvers, who taught their craft over generations, roughed out the statues using stone tools called toki and employed sharp obsidian tools to make finer lines. The real mystery—how a small ...

Obsidian is my favorite productivity tool. I use it for all of my writing, as a journaling app, and to replace multiple productivity tools. There's a big downside, though: no grammar checking tool.

It’s fine structure means both that it fractures predictably during tool-making and it will produce a razor sharp edge. But, what ultimately makes obsidian so well suited for tracking social relations ...