Minerals and Metals in Ancient India v1.c11.s8.3

v1.c11.s8.3

Almost all the seals are coated or have been coated with a smooth glassy-looking substance which was at first thought to be the remains of a glaze, whose colour has entirely disappeared. All the seals have been carefully examined for traces of colour, but without success. But the same seals of Mohenjo-Daro and Harappa which have been found at Kish in Mesopotamia contain traces of original blue or green colouring. There is no evidence that seals of Mohenjo-Daro were originally coloured. If these were so coloured, all traces of the pigment have entirely disappeared through long deposit in the damp and salty soil of the site. Sana Ullah has made an exhaustive analysis of the surface coating on one of these seals which has given the following results: