Part 5 - Glass industry of the Vārāṇasī region

From the PGW times glass manufacturing was known in the Gaṅgā plains. Sites like Śrāvastī or Hastinapur yielded some samples of coloured and plain glass beads and bangles. Presence of iron, aluminium, cobalt caused different colours like brown, black or light green. So a considerable technical knowledge was gathered in an early date of PGW phase. More than 400 beads were discovered at Vārāṇasī and most of them are coloured. Of them at least two dozen came from period I (800-200 BCE). Six of them are black, five of different shades of blue, five of green and three of opaque red. Five beads of this period were taken for chemical analysis. Various chemical compounds are mainly the colouring agents. Otherwise the glasses were nothing other than soda-lime silicate or potassium soda-lime silicates. The glass beads are translucent and microscopic study found presence of air bubbles, responsible for that.

In the primary stage of melting these bubbles are formed and to remove them heating of much higher degree was required. That was not attained by the early glass craftsmen of Vārāṇasī. Leaving aside minor defects the glass manufacturing process was conforming to the scientific glass producing method and probably that’s why they are still in a good state of preservation. All these point to the existence of a specialized professional class of glass makers.^[1] From period II variety of glass beads started appearing. They displayed a remarkable colour variation ranging from black different hues of blue, green and opaque glass. Copper was the main colouring agent in these glass beads and silica was the main ingredient of these beads.

The silica content varied from 65 to 70%. Lead was completely absent in these beads while it has been reported from Taxila beads. Moreover opaque copper red glass contained lead elsewhere but lead was not found in Rajghat specimens of this class. This suggests existence of a very advanced and skilled local manufacturing of these beads. From period III or the beginning of the Christian era this industry was even more flourished. Many more beads of many new colours were recovered and glass bangles were also reported from this stage. Colour compositions of glass items showed a clear understanding of chemical properties of the substances by the craftsmen.^[2]