Reference
Note:
Hartill (GCC, p. 117) follows Thierry (CMV, pp. 17-19) in attributing these zinc issues to the period 1746 – 1774, terminated by the fall of the Nguyễn Lords (阮氏(阮家)). The view that the coin is of zinc or zinc alloy rather than brass is occasioned by the type of corrosion and the style which was only used by mints issuing zinc coins.