Such highly polished beads were the longest pierced carnelian beads produced prior to diamond-drilling. They were made in specialized workshops, and required sophisticated drilling techniques to perforate. It has been calculated that a bead of this length took at least 64 hours to drill; and since the strain of drilling required periods of rest every few hours, at least 10 days went into its manufacture. The stone came from the mines of Gujarat, and finished beads were exported as far as Mesopotamia and the Persian Gulf. The Indus Valley cities established an outpost at Shortughai in northern Afghanistan to give them access to lapis lazuli and turquoise, but they preferred and valued carnelian for its hardness. Beads like this were greatly prized, and have been found in the royal cemetery at Ur.
An archaeological find at Mehrgarh has provided a surprising context for the highly developed skill of drilling in the Indus Valley. Eleven drilled molar crowns from nine adult skulls were discovered in a neolithic graveyard that dates from 9,000 to 7,500 years ago. This very precise proto-dentistry was accomplished with bow-drills tipped with flint.