Excavations at the Mature Harappan site of Rakhigarhi in Haryana have uncovered a unique industrial office belonging to the Master of the Royal Potter's-Slip. The site yielded a collection of terracotta tablets and inscribed ceramic jars containing residues of rare mineral pigments, including specular hematite and high-grade kaolin, used to create the iconic red-and-black Harappan pottery.
The tablets contain symbolic notations that researchers believe represent standardized formulas for mixing liquid slips, ensuring that pottery produced across different sectors of the city-state maintained a uniform aesthetic and durability. This find highlights the level of industrial oversight in Indus Valley craft production, where even the visual branding of utilitarian goods was governed by a central administrative authority.