Much like in Sumer, a unicorn statue was featured on the New Year’s parade. The clay figure of a unicorn was placed on a tall pole and carried at the lead of the procession. This Vedic story celebrated in the pre-cursor to this parade featured a sexual union of a prostitute and a formerly celibate bard.
The horn for the unicorn was thought to be the only material strong enough to form a parīśāsau, which was used in a Vedic ritual involving an earthenware vessel being filled with molten metal.
The seals themselves are made from dolomitic steatite, requiring a furnace able to generate heat in excess of 1200 degrees Celsius.
We don’t know enough of the civilization of the ancient Indus valley, but we do know there was active trade with Sumer, as objects unique to each culture have been found in the archaeological record of the other.