Ash has been a source of grey colour since pottery began — wood ash glazes on ceramics produce characteristic grey-green effects from mineral content. In Japanese ceramic tradition, natural ash glazes (from wood fired kilns) are among the most prized effects. The colour ash in contemporary design references both the natural material and the quality of things that have passed through fire.

Quiet, processed, and slightly melancholic. Ash is what remains after fire — all combustibility gone, only mineral permanence remaining. It carries the paradox of destruction and purification simultaneously. Associated with aftermath, with what endures, and with the particular kind of beauty that emerges from simplification. In Japanese aesthetics, ash grey embodies wabi-sabi — the beauty of impermanence and incompleteness.

The Ash Wednesday ceremony in Catholic and Anglican traditions — marking the forehead with ash — uses the colour and material as a memento mori: "Remember you are dust and to dust you shall return." The ash Wednesday mark connects every participant to the same grey colour of mortality. Pompeii's preservation under volcanic ash is perhaps the most dramatic example of the paradox at the heart of ash: the same material that destroys also preserves.