History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c17.s2.t1.4

v1.c17.s2.t1.4

The patterns of the Type I beads were made by using as paint a coat of alkali, such as carbonate of soda and then fixing it by heat. The paint is left with a glossy white surface and adheres to the stone so firmly that it is almost impossible to remove it by simple means. The technique is still carried on in Persia, on the borders of China and sporadically in Sindh. In the last province, the juice of a plant is mixed with alkali, presumably to keep it from flaking off the stone before it has been made fast by heat.