The monetary use of ingots made from tin (one of Malaysia's richest natural resources) was adapted into a coinage system in the Malay sultanate of Pahang. The ingots were originally in the form of a small pyramid-like mountain. In the 1860s small symbolic representations of the ingots were issued as coinage, valued in terms of the Mexican dollar. This example was intended to circulate as a four cent piece.The square coins are hollow inside, resembling a hat, and have a flat, decorated rim with Malay inscriptions that indicate their monetary role. The shape of these coins has earned them the name 'tin-hat' money.