Minerals and Metals in Ancient India v1.c11.s8.7

v1.c11.s8.7

Mackay is also of the same opinion when he says that there is no doubt that after being cut and engraved, these seals were treated in some way to produce the white coat that covers them. Horace Beck, after microscopically examining the white coating, has came to the conclusion that it is not a slip, but was made by painting the surface with an alkali and then subjecting it to heat. Sometimes this coat shows a certain amount of lamination caused either by the alkali being applied in more than one coat or by the overlapping of brush marks.