*4.1. Yehud Gerah Type 5 O1/R1*

Multi-focal LM observation of the Type 5 O1/R1 coins revealed well-preserved silver metal depicting a helmeted head of Athena on the obverse and an owl on the reverse (Figure 5a–c). On the right field of the reverse of the coins, the Paleo-Hebrew inscription YHD appears (Figure 5a and Supplementary Materials, Figure S2b).

The bright areas observed in the SEM BSE mode are silver metal regions and the dark areas according to BSE mode are covered with oxides and some corrosion products (Figure 5d). The SEM-EDS analysis results of eight specimens of the Yehud *gerah* Type 5 O1/R1 coin surfaces (obverse and reverse, Figure 5d, and Supplementary Materials, Figure S2) revealed that the coins were composed of silver, though other elements were also detected, including Cu, Sn, O, Si, Cl, Al, Ca, P, and S (Supplementary Materials, Table S1).

The alloy of the coins revealed a composition of 93.2–100 wt% Ag and up to 6.8 wt% Cu (Supplementary Materials, Table S1), where the average value of the coins' alloy composition after omitting the peaks of oxides, corrosion products, and soil elements was 98.5 ± 2.0 wt% Ag and 1.5 ± 2.0 wt% Cu (where 42 different areas of the Type 5 O1/R1 coins' obverse and reverse sides were measured). It seems that a silver content of approximately 97% was the equivalent of "pure silver". This is entirely to be expected, because elemental silver as measured by modern scientific equipment would not have been available in antiquity. The closest refined silver bullion that could have been achieved by traditional smelting and refining processes would also include traces of gold, lead, and bismuth [2] (p. 334, n. 31).

IAA 153976 coin revealed a different alloy composition of 38.5–100 wt% Ag and up to 61.4 wt% Cu (Supplementary Materials, Table S1). Therefore, this coin was not included in the average composition value and standard deviation (SD) calculations of group Yehud *gerah* Type 5 O1/R1.

**Figure 5.** Images of the Yehud *gerah* Type 5 O1/R1 coins: (**a**) IAA 138139 reverse, depicting an owl (multi-focal LM), and (**b**–**d**) obverses of the coin depicting the head of Athena; (**b**) IAA 138139 (multifocal LM); (**c**) IMJ 27398 (multi-focal LM); and (**d**) IMJ 27398 (SEM, BSE mode), where the white squares (areas 1 and 2) were examined by EDS analysis (the brighter areas are better preserved metal than the darker areas).
