紫土

しど

紫土 is a rare manganiferous earth pigment for purple, a material relative of the dye-based 紫.

Tobunken's 彩色DB records 紫土 (purple earth) used in a 752 CE Shōsōin document.

Earth-pigment context only; it does not supply a measured value for the dye-based purple 紫.