Hebron's furnaces melt recycled bottle glass with iron and copper oxides into colours named after stones — cobalt, turquoise, bottle green, amber, rose. The colour lives in the body of the vessel, not on its surface.

So this system is built the way a blown vessel is: a deep cobalt mass that reads almost black in the dim of the workshop, walls that thicken and thin across a single form, seeds and striations left in from the batch, and a copper-blue turquoise that only shows itself when light passes through.