The knot as a symbol means wisdom among the Akan - NYANSA POW - wisdom knot.
The Akan occupy a large area of West Africa stretching from the South-West of Ghana to the South-East of the Ivory Coast
The use of scales and weights originally came from the Islamic north. The Akan used these weights for the best part of five centuries. They are made of brass which is an alloy of zinc and copper using the lost wax process. The ratio of the alloy can vary according to the location and the period. As the lost wax name implies each weight is unique, the mould being destroyed as the weight sees the first light of day. The sacking of Kumasi by the British in 1874 was the beginning of the end for the use of gold dust as a form of money and was completely outlawed by the British 1896.
Lit.: African Goldweights - Miniature Sculptures from Ghana 1400-1900. Tom Phillips - page 129