**6. Conclusions**

In this study, 50 Late Persian period and Macedonian period silver coins were studied by NDT metallurgical analysis. The results obtained from the SEM-EDS surface analysis of well-preserved areas sufficiently represent the concentrations of the coins' ground bulk. Correspondence was received between the SEM-EDS analysis results and the XRF analysis results. The results show that the coins are made of high purity silver with only small percentages of copper. All the coins were produced by similar techniques of casting flans and striking them by plastic deformation. Based on the average alloy composition values and SD, as well as the copper concentration distribution of the examined series, the five die combination issues of the Yehud series Type 5 O1/R1–O1/R5, Type 16 O2/R2, Type 24 O1/R2, and Type 31 O1/R1 groups, and the late addition Yehud coin type, each series was most likely produced by a different and controlled specific composition of silver–copper alloy. However, four Type 5 exceptional coins (IAA 153976 O1/R1, IAA 154383 O1/R2, IMJ 27387 O1/R2, and IAA 153981 O1/R4) revealed a different alloy composition with a much higher amount of copper and heterogeneity. This implies that at a certain stage of the minting process, a different batch of possibly recycled alloy was used instead of the standardized alloy that was recorded for all other coins of the same die connection. The current four-step methodology revealed novel information concerning the material culture of the southern Levant during the Late Persian period associated with minting production of silver coins. This four-step methodology can be used with additional bulk NDT methods by other researchers to study various ancient silver objects.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/ma16062200/s1, Figure S1. SEM-EDS analysis showing the spectra of a typical Yehud *gerah* silver coin (Type 5 O1/R3, IAA 153978, reverse); Figure S2. Images of the Yehud *gerah* Type 5 O1/R1 coins: (a) IAA 138139 reverse depicting an owl (SEM, BSE mode); (b) IAA 138139, reverse (multi-focal LM) showing the Paleo-Hebrew inscription YHD (Yeh[u]d); (c) IMJ 27398 obverse depicting a helmeted Athena (SEM, SE mode); (d) IMJ 34543 reverse depicting an owl (SEM, BSE mode); and (e) IMJ 34543 obverse depicting a helmeted Athena (SEM, BSE mode). The areas inside the squares were examined by EDS analysis; Table S1. SEM-EDS analysis results of the Yehud *gerah* Type 5 O1/R1 coins, where SA represents the scanned area. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Figure S3. Images of Yehud *gerah* Type 5 O1/R2: (a) coin IAA 154383, reverse (multi-focal LM), showing the face of an owl; and (b) IAA 154383, reverse (SEM, BSE mode), where the bright areas represent shiny silver metal and the dark areas are covered with oxide and corrosion products. The areas inside the squares were examined by EDS analysis; Table S2. SEM-EDS analysis results of the Yehud *gerah* Type 5 O1/R2 coins, where SA represents the scanned area. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Figure S4. Yehud *gerah* Type 5 O1/R3, IAA 153978 (obverse), SEM–EDS elemental mapping: (a) general view of the examined area; (b) the detected elements (Ag, Ca, O, Cl), where the green areas are rich in silver and red areas are rich in chlorine; (c) presence of Ag; (d) presence of Ca; (e) presence of O; and (f) presence of Cl; Table S3. SEM-EDS analysis results of the Yehud *gerah* Type 5 O1/R3 coins, where SA represents the scanned area. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Table S4. SEM-EDS analysis results of the Yehud *gerah* Type 5 O1/R4 coins (each scanned area was 300 μm × 300 μm). Only bright areas according to BSE mode of shiny metal were examined by EDS analysis. RH represents Ramallah Hoard (nos. 2–6); Table S5. SEM-EDS analysis results of the Yehud *gerah* Type 5 O1/R5 coins. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Figure S5. Yehud half *gerah* Type 16, O2/R2 coin, reverse depicting a falcon in flight: (a) Edom hoard no. 4 (SE mode); (b) Edom hoard no. 5 (SE mode); and (c) Edom hoard no. 6 (BSE mode), where the brighter areas according to the BSE mode are better preserved than the darker areas. The areas inside the squares were examined by EDS analysis; Table S6. SEM-EDS analysis results of the Yehud half *gerah* Type 16 O2/R2 coins. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Figure S6. SEM images of the Trans-Jordan hoard Type 24 O1/R2, obverse depicting a facing head: (a) coin Trans-Jordan hoard no. 11 (SE mode); (b) coin Trans-Jordan hoard no. 13 (SE mode); (c,d) coin Trans-Jordan hoard no. 12 (SE mode and BSE mode, respectively). The areas inside the squares were examined by EDS analysis; Table S7. SEM-EDS analysis results of the Yehud quarter *obol* Type 24 O1/R2 coins, where SA represents the scanned area. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Figure S7. SEM images of the Yehud *hemiobol* Type 31, O1/R1, reverse depicting a bird standing right, head reverted: (a) IMJ 34593 (BSE mode); and (b) IMJ 34591 (SE mode). The areas inside the squares were examined by EDS analysis; Table S8. SEM-EDS analysis results of the Yehud *hemiobol* Type 31 O1/R1 coins, where SA represents the scanned area. Only bright areas according to BSE mode of shiny metal were examined by EDS analysis; Table S9. SEM-EDS analysis results of the Yehud IAA 153976, IMJ 27424, IAA 101006, IAA 154383, IMJ 27383, Trans-Jordan hoard no. 11, and IMJ 34591 coins after roughly grinding the surface; Figure S8. The copper distribution of each silver coin group based on SEM-EDS chemical analysis results, where the Cu wt% concentration is presented vs. the relative no. of measurements (%): (a) Yehud *gerah* Type 5 O1/R1; (b) Yehud *gerah* Type 5 O1/R2; (c) Yehud *gerah* Type 5 O1/R3; (d) Yehud *gerah* Type 5 O1/R4; (e) Yehud *gerah* Type 5 O1/R5; (f) Yehud half *gerah* Type 16 O2/R2; (g) Yehud quarter *obol* Type 24 O1/R2; and (h) Yehud hemoibol Type 31 O1/R1; Figure S9. Yehud *gerah* coins Type 5 O1/R1 (ca. 350–333 BCE) (Athena/Owl): IAA 138139, IAA 153975, IMJ 27424, IMJ 27398, IMJ 34542, IMJ 34539, IMJ 34543, and IAA 153976; Figure S10. Yehud *gerah* coins Type 5 O1/R2 (ca. 350–333 BCE) (Athena/Owl): IAA 101006, IAA 177246, IAA 153977, IMJ 34538, IMJ 34553, IMJ 34537, IMJ 34554, IMJ 34620, IAA 154383, and IMJ 27387; Figure S11. Yehud *gerah* coins Type 5 O1/R3 (ca. 350–333 BCE) of the Yehud series (Athena/Owl): IAA 153979, IAA 153978, IMJ 34555, and IMJ 27425; Figure S12. Yehud *gerah* coins Type 5 O1/R4 of the Yehud series (Athena/Owl): RH2-RH6, IAA 153980, IMJ 34556, and IAA 153981; Figure S13. Yehud *gerah* coins Type 5 O1/R5 (ca. 350–333 BCE) of the Yehud series (Athena/Owl): IMJ 34558, and IMJ 27388; Figure S14. Yehud coins Type 16 O2/R2 (Persian king wearing a jagged crown/Falcon in flight) (ca. 350–333): Edom hoard nos. 1–6, IMJ 27383, IMJ 27414, and IMJ 34566; Figure S15. Yehud Attic standard quarter *obol*, Type 24 O1/R2 (Facing head/Owl) of the Macedonian period (ca. 320(?)–312 BCE): Trans-Jordan hoard nos. 11, 12, 13; Figure S16. Yehud coins Type 31 O1/R1 (Head of roaring lion/bird standing right, head reverted) (ca. 306–302/1 BCE): IMJ 34631, IMJ 34593, IMJ 34591, IMJ 34709, IMJ 34594, and IMJ 34715.

**Author Contributions:** Conceptualization, M.C., D.A., H.G. and O.T.; study objectives, M.C., D.A., H.G. and O.T.; research methodology, M.C., D.A., H.G. and O.T.; formal analysis, M.C. and D.A.; discussion of results, M.C., D.A., H.G. and O.T.; conclusions, M.C., D.A., H.G. and O.T.; writing introduction, H.G. and O.T.; writing—technological background to research, M.C. and D.A.; writing original draft preparation, D.A.; project administration, H.G. and O.T.; funding acquisition, H.G. and O.T.; supervision, O.T. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research forms part of an Israel Science Foundation (ISF) project (No. 2883/20); Corpus of Samarian Coinage (ca. Fourth Century BCE); PI: Oren Tal.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data supporting the reported results can be found in the Supplementary Materials file.

**Acknowledgments:** The authors are indebted to the ISF and would also like to thank Tomer Reuveni from the Wolfson Applied Materials Research Center at the Tel Aviv University for his SEM technical assistance. We are also grateful to Robert Kool, head of the coin department at the IAA, for providing the controlled archaeological excavation coins for our project.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
