Minium is a naturally occurring orange-red lead tetroxide. Its synthetic analogue is called red lead.
Both minium and red lead give a vibrant orange colour and have been used extensively by illuminators. Minium was one of the illuminator's cheapest pigments because it was a by-product of the industrial extraction of silver.
Minium and red lead cannot be easily distinguished with the analytical methods used for this project; the two terms are therefore used interchangeably throughout this website, unless noted otherwise.