The weights were used primarily for market exchange but may also have been used for taxation. The Harappan stone weights are distinct from West Asian weights. However, the system is identical to that used by the First Kingdoms of the Gangetic Plain around 300 B.C.E. and is still in use today in traditional markets throughout Pakistan and India. The Harappans used hexahedra, popularly known as cubical weights of chert and agate, adhering to a predetermined standard adopted throughout the Indus. The stone weights vary in size from 1.1 * 1.7 * 0.7 cm to 4.1 * 4.1 * 3.4 cm. The weights are based on a complex system of measurements that are calculated by both binary and decimal increments. This level of standardisation indicates a well-developed network of internal trade.
c. 2500–1900 BCE