"Indus beadmakers have the distinction of producing the longest and most slender beads of carnelian in the world, prior to the advent of diamond drilling," (J.M. Kenoyer). Chanhu-daro has provided the most data about the manufacture of these long carnelian beads, seen here in a necklace or belt from Mohenjo-daro's DK Area. It could take weeks of intense labor to create one bead, some nearly 5 inches long, with much breakage along the way.
See also Dorothy Mackay's article Finds at Chanhu-daro.