History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c17.s2.t2.3

v1.c17.s2.t2.3

Among all the beads found from Chanhu-daro, the pile of minute steatite beads was an exceptional find. The manner in which these beads lay in lines on the pile proved that these were originally strung together. F.A. Bannister and G.F. Claringbull of the Mineral Department of the British Museum who examined some of these beads, reported that the beads are small hollow cylinders which vary in external diameter 1/2 (.019 inch) to 1 mm and in length from 1/2 to 1 1/2 mm. When freed from loosely adherent soil, they are pure white and very hard. Nearly every bead is furrowed along its length spirally, always in a clock- wise direction. It is not uncommon to find two beads joined together with the spiral furrowing running continuously and in perfect alignment from one to the other. The physical and chemical data are conclusive about the material from which these beads were made. Their specific gravity is 2.85 and the refractive index of crushed fragments is 1.60. The beads can be fused only in the electric arc, and then yield glassy spheres with a lower specific gravity 2.72. Except magnesium and silicon no other element could be detected with the quartz spectrograph. X-ray powder photographs show that the beads are steatite that has been completely dehydrated and heated to a temperature exceeding 1200°C.