History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c17.s2.t1.5

v1.c17.s2.t1.5

It is uncertain what medium was used to produce the black coloured patterns on the type II beads. The white back-ground was formed by flooding the red carnelian with the alkali, thus creating a white opaque surface. According to Horace Beck it is also possible that a copper solution was used as the paint. Thus to apply fine and even lines and firing on the beads, the greatest skill must have been required.