Zaffre
From London's Ghost Acres
A deep blue pigment obtained from roasting cobalt ore. Used to impart a blue hue to glass or to prepare smalt.
https://en.wikipedia.org/wiki/Zaffre
A deep blue pigment obtained from roasting cobalt ore. Used to impart a blue hue to glass or to prepare smalt.
https://en.wikipedia.org/wiki/Zaffre