Ag and Sn Implications in 3-Polker Coins Forgeries Evidenced by Nondestructive Methods

Abstract

Several forged 3-Polker coins have been reported in historical sources on the financial crisis that occurred between 1619 and 1623 at the start of the 30-year-long war. Supposedly, belligerent countries forged other countries’ coins which were then used for external payments as a war strategy. Thus, a lot of 3-Polker coins (e.g., Sigismund-III-type) were forged, and the markets became flooded with poor currency. In the present day, these pre-modern forgeries are rare archeological findings. Only five forged 3-Polker coins randomly found in Transylvania were available for the current study. There are deeper implications of silver and tin in the forgery techniques that need to be considered. Thus, the forged 3-Polker coins were investigated via nondestructive methods: SEM microscopy coupled with EDS elemental spectroscopy for complex microstructural characterization and XRD for phase identification. Three distinct types of forgery methods were identified: the amalgam method is the first used for copper blank silvering (1620), and immersion in melted silver (1621) is the second one. Both methods were used to forge coins with proper legends and inscriptions. The third method is the tin plating of copper coins (with corrupted legend and altered design) (1622, 1623, and 1624). The EDS investigation revealed Hg traces inside the compact silver crusts for the first type and the elongated silver crystallites in the immersion direction, which are well-attached to the copper core for the second type. The third forgery type has a rich tin plating with the superficial formation of Cu6Sn5 compound that assures a good resistance of the coating layer. Therefore, this type should have been easily recognized as fake by traders, while the first two types require proper weighing and margin clipping to ensure their quality.

Sustainable Approach to Metal Coin Canceling Methods, Using 3D Modeling and Finite Element Method Analysis

“…These factors may lead collectors or interested customers to experience, on one hand, apprehension about acquiring an item of little value that they do not truly require [6]; on the other hand, they must also take into account the inclination to purchase the piece with the intention of capitalizing on it later at a higher price. Today, the specialty literature [4,10,15] records a large number of canceled 50 and 100 lei nickel coins, as presented in Figure 3.…”

“…But, to date, the exact number of melted pieces of the withdrawn coins which remained on market is still unknown. These factors may lead collectors or interested customers to experience, on one hand, apprehension about acquiring an item of little value that they do not truly require [6]; on the other hand, they must also take into account the inclination to purchase the piece with the intention of capitalizing on it later at a higher price.…”

“…Following the circulation period, coin withdrawal is necessary, and it is also mandated by legal provisions, terms and conditions [5]. Valueless coins are retracted and, following the sustainable reuse of the metal alloy, are subjected to melting [6].…”