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1- Tehran University
2- Tehran University ,majidzohouri@ut.ac.ir
3- Tehran. Sharif University
2- Tehran University ,
3- Tehran. Sharif University
Abstract: (130 Views)
Various aspects of coins, including their material, purity, weight, and minting processes, reflect societies’ economic, political, and social conditions throughout history. This principle is not confined to any specific historical period, it has been a continuous reality from the ancient era to the present, for example, the levels of impurities were increased during the kingdom of Peroz I in the Sasanid dynasty due to internal and external conflicts (ancient era), the gold of eighth shia imam’s dome was used for minting the coin to pay soldiers' wages during the kingdom of Nader’s descendants, and even changing the materials, weight, and minting mechanism in the second Pahlavi period (contemporary era). In other words, the economic conditions of each government clearly reflect in the quality and type of coins that are minted by them. During the second Pahlavi era that is examined in this study, nine different coins with various nominal values were minted in different forms and types. Among these, the 50-dinar coin stood out as one of the few minted almost continuously throughout this period. Therefore, investigating the material, weight, and minting mechanisms of different types of 50-dinar coins provides valuable insights into the government conditions during the second Pahlavi era. The conducted research revealed that the first type of 50-dinar coins, minted in 1943 from copper, was soon replaced due to poor corrosion resistance by a second type known as bronze (copper/tin) coins. However, elemental analysis indicated that the alloy used in these coins was brass (copper/zinc), contrary to all sources such as articles, books and even CBI catalogues. The main reason for using brass instead of bronze was the lower price of zinc in comparison with tin used in brass and bronze, respectively. However, the misreporting of this issue across reputable sources might stem from a lack of knowledge in properly classifying copper alloys. The minting of these so-called bronze coins continued with two different weights until the mid-1970s. The thickness reduction due to weight loss is clearly indicated in the optical microscope images provided from the cross-section of these coins (Figure 10). It’s worth mentioning that the two main reasons for reducing the weight of the 50-dinar bronze coins were rising global copper prices and economic sanctions against Iran during the premiership of Mossadegh. Eventually, rising inflation caused the metal's value to exceed the coin’s nominal value, and the impracticality of minting coins with lower weights led to a change in the coining production process from normal rolling to roll bonding (sandwich rolling) before minting in 1354. These changes enabled the production of coins with a core made of a low-value metal (iron) and a surface made of corrosion-resistant alloys (copper alloys). These coins exhibited sufficient strength and corrosion resistance due to their iron core and copper-based alloy coating, respectively This three-layer structure is depicted in the scanning electron microscope images taken from the cross-section of the coins produced with the sandwich rolling method (Figure 15). The minting of 50-dinar coins using the roll bonding mechanism continued not only until the last year of the Pahlavi era 1979 (the occurrence of the Islamic Revolution and regime change), but also into the early Islamic Republic era, lasting until one year after the islamic revolution. Consequently, the 50-dinar coin became the first and last coin to feature the lion and sun symbols under the Islamic Republic regime.
Technical Note: Original Research |
Subject:
Archaeometry
Received: 2024/10/19 | Accepted: 2025/05/11
Received: 2024/10/19 | Accepted: 2025/05/11
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