Black Obsidian

When lava meets water and cools too rapidly to crystallise, the result is this natural glass. Mineralogically, it is not a stone—classified as an amorphous solid.

The Aztecs fashioned obsidian into blades and mirrors. Fractured, it breaks conchoidally, producing an edge thinner than a steel scalpel. Some surgical blades still use obsidian today.

In Japan, obsidian has been in use since the Jōmon period, with Shirataki in Hokkaido and Kirigamine in Nagano as key sources. Trace the trade routes of the Stone Age, and they map onto the distribution of obsidian. One stone, outlining an ancient network.

Sunday evening. He opens next week's calendar and asks himself which of these commitments actually need to exist. Not everyone audits their own schedule with that precision. Ambiguity left unresolved makes him uncomfortable — not about others, about himself. This stone works well in that hand. The rigour is internal. It always was.