Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao
<p>Sarcophagus and part of the body of the Lady of Cao (after Ref.). She was 1.48 meters tall, was 25 years old and died of eclampsia. The face of the Lady is covered by bowl 073, which is gilded copper, while the body is resting on 23 ceremonial spear throwers covered with gilded copper.</p> "> Figure 2
<p>Portable EDXRF equipment for EDXRF analysis and for linear scanning, composed of a Si-drift detector (on the right; 123 SDD: 450 μm thickness, 7 mm<sup>2</sup> area and 130 eV energy resolution at 5.9 keV) and an X-ray tube (on the left; 40 kV, 100 μA maximum voltage and current and Ag-anode). Bias supply and MCA are inside the detector and of the X-ray tube, respectively. A typical measurement takes 50 s. The X-ray tube is collimated and irradiates an area of <1 mm<sup>2</sup>.</p> "> Figure 3
<p>Distribution of EDXRF measurements of the 41 golden areas of the 43 nose ornaments from the tomb of the Lady of Cao.</p> "> Figure 4
<p>Typical X-ray spectrum of an Au-Ag-Cu alloy reference sample (70% Au, 25% Ag, 5% Cu) obtained with the equipment shown in <a href="#heritage-06-00328-f002" class="html-fig">Figure 2</a>. The X-ray peaks are, from left: Cu-Kα line (8 keV), Au-Ll (8.5 keV), Cu-Kβ (8.9 keV), Au-Lα (9.7 kev), Au-Lβ (11.5 keV), Au-Lγ (13.4 and 13.8 keV), Ag-Kα (22 keV) and Ag-Kβ (25 keV). The small peaks between Cu-Kα and Cu-Kβ and between Au-Lα and Au-Lβ correspond to Au-Lη (8.5 keV) and Au-Ll (10.3 keV) lines, which have an intensity of 5% and 2.5%, respectively, considering 100 as the intensity of Au-Lα line.</p> "> Figure 5
<p>Distribution of EDXRF measurements of the 41 silver areas of the 43 nose ornaments, from 2 to 112. The large spread of concentration and the high gold concentration are remarkable.</p> "> Figure 6
<p>Images (<b>a</b>–<b>c</b>) show nose ornament 002, while image (<b>d</b>) shows the related radiography along with gray level profile along red line. The two silver hats were possibly glued to the golden body, while the two silver shields were possibly pressed to the body like a button. The last Figure shows, from the left, the level of the silver hat alone (A), the level of the hat superimposed onto the golden body (B).</p> "> Figure 7
<p>Front and rear side of nose ornament 105 (<b>a</b>,<b>b</b>), its radiography and the grey level profile (along red line) of the gold-silver interface (<b>c</b>,<b>d</b>). A clear difference may be observed between the gold and the silver areas. This nose ornament is in bad condition and was undergoing restoration. The fragment studied by Ingo et al. was taken from the face on the top right of Figure (<b>a</b>). The soldering material was an Ag-Cu alloy, as shown by EDXRF-measurement (<b>e</b>).</p> "> Figure 8
<p>Nose ornament 106 (top figures, front and rear) (<b>a</b>,<b>b</b>) and its radiography with grey numbers (<b>c</b>). The radiography clearly shows that the five silver heads have been soldered to the gold semi-circles on both sides. The scan along the red line (grey levels) shows from the right the golden area, the soldering area (B) and the silver area (A) (<b>d</b>).</p> "> Figure 9
<p>Images (<b>a</b>–<b>c</b>) representing the front side of nose ornament 022 and the related radiography (<b>d</b>) with the corresponding grey level profile along the red line shows the clear discontinuity between grey level profile along the red line shows the clear discontinuity between the gold and silver areas.</p> "> Figure 10
<p>Images (<b>a</b>–<b>c</b>) representing the front side of nose ornament 024 and the related radiog-raphy (<b>d</b>) with the corresponding grey level profile along the red line (A-B in <a href="#heritage-06-00328-f007" class="html-fig">Figure 7</a>c). This shows the clear discontinuity between the gold and silver areas.</p> "> Figure 11
<p>Images (<b>a</b>,<b>b</b>) representing the front and back side of nose ornament 030 and the related radiography (<b>c</b>,<b>d</b>) showing the discontinuity between gold and silver areas. It may be that the gold-silver junction has been produced by a Hg amalgam.</p> "> Figure 12
<p>(<b>a</b>) The front and (<b>b</b>) rear sides of nose ornament 018 are perplexing. The gold areas on the rear side are partially blackened. (<b>c</b>) The radiography shows an unclear discontinuity between gold and silver (hair) and (<b>d</b>) the grey level of the red line interval A–E.</p> ">
Abstract
:1. Introduction
2. Depletion Gilding
3. Materials
4. Methods
5. Results
5.1. EDXRF Analysis of Gold and Silver Nose Ornaments
5.2. Attenuation Measurements Using Monoenergetic X-rays
6. Discussion
- Soldering, using a silver alloy (sometimes a silver-copper alloy), as in the case of nose ornament 105 (see Figure 7). The soldering with Ag is demonstrated by the EDXRF-spectrum of the soldering area, showing an excess of Ag.
- Using a mercury amalgam with a heating process, as in the case of nose ornament 011 [25], where Hg was clearly detected in the interface of Au-Ag and possibly in many other nose ornaments.
- Using a hammering-heating process with a temperature sufficient to soften the silver alloy, as in the case of nose ornament 024.
7. Conclusions
- A.
- All gold areas have a similar composition.
- B.
- Silver areas have quite an erratic composition.
- C.
- Silver areas show, besides silver and copper, an unusually high concentration of gold of up to 35%.
- Radiographs, carried out on about 15 nose ornaments, clearly show that two separate sheets of gold and silver alloy had to be used and joined together.
- Attenuation measurements with monoenergetic radiation, which quantitatively confirmed not only the hypothesis of two sheets of Au and Ag, but also determined that the two sheets have different thicknesses (Ag-sheets are approximately two times thicker than the Au-sheets).
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Appendix A
Museum LADY OF CAO (Magdalena de Cao, Trujillo, Peru) The site Museum Lady of Cao gives a complete overview of the El Brujo Archaeological Complex and the many ancient objects that were found there, including funeral objects, tools and gold and silver jewelry. The tomb of the Lady of Cao was discovered in 2006 by a team of Peruvian archaeologists directed by Régulo Franco Jordán. The 1500-year-old mummy of the Lady of Cao, heavily tattooed and well preserved, shed new light on the Moche culture, which occupied Peru’s northern coast from about 100 to 700 CE. | |
Object picture (front and, in a few cases, back side) | Code (PACEB-F4-00X) and Gold composition: Au(%), Ag(%), Cu(%) Silver composition: Ag(%), Cu(%), Au(%) |
PACEB-F4-002 (gold and silver alloy) Gold: 75.5, 19, 5.5 Silver: 99, 0.2, 0.8 | |
PACEB-F4-003 (gold and silver alloy) Gold: 79.5, 16, 5.5 Silver: 83, 7.5, 9.5 | |
PACEB-F4-004 (gold and silver alloy) Gold: 82, 14.5, 3.5 Silver: 92, 4.5, 3.5 | |
PACEB-F4-005 (silver alloy) Silver: 70, 20, 10 | |
PACEB-F4-006 (gold and silver alloy) Gold: 79.5, 16, 4.5 Silver: 92, 4, 4 | |
PACEB-F4-007 (gold and silver alloy) Gold: 80.5, 15.5, 4 Silver: 87, 5, 8 | |
PACEB-F4-008 (gold and silver alloy) Gold: 82, 15, 3 Silver *: 50, 20, 30 | |
PACEB-F4-009 (gold and silver alloy) Gold: 84, 14.5, 1.5 Silver *: 80, 12, 8 | |
PACEB-F4-010 (gold and silver alloy) Gold: 82, 14.5, 3.5 Silver *: 60, 15, 25 | |
PACEB-F4-011 (gold and silver alloy) Gold: 81.5, 14, 4.5 Silver: 62, 23, 15 | |
PACEB-F4-012 (gold and silver alloy) Gold: 80, 16, 4 Silver: 46, 35, 19 | |
PACEB-F4-013 (gold and silver alloy) Gold: 78, 19, 3 Silver: 85, 11, 4 | |
PACEB-F4-014 (gold and silver alloy) Gold: 81, 14, 5 Silver: 60, 19, 21 | |
PACEB-F4-015 (gold and silver alloy) Gold: 75.5, 20.5, 4 Silver: 62, 14, 24 | |
PACEB-F4-016 (gold and silver alloy) Gold: 79.5, 16, 4.5 Silver: 73, 14, 13 Hg in the Au-Ag interface | |
PACEB-F4-017 (gold and silver alloy) Gold: 78.5, 16.5, 5 Silver: 64, 16, 20 | |
PACEB-F4-018 (gold and silver alloy) Gold: 75, 19.5, 5.5 Silver: 73, 19, 8; disks: 85, 8, 7 | |
PACEB-F4-019 (gold and silver alloy) Gold: 78, 17, 5 Silver: 88, 4, 8 | |
PACEB-F4-020 (gold and silver) Gold: 82.5, 14, 3.5 Silver: 77, 21, 2 | |
PACEB-F4-021 (gold and silver alloy) Gold: 81.5, 14.5, 4 Silver *: 55, 30, 15 | |
PACEB-F4-022 (gold and silver alloy) Gold: 79, 15.5, 5.5, Silver: 68, 18, 14 | |
PACEB-F4-023 (gold and silver alloy) Gold: 82, 14.5, 3.5 Silver: 76, 12, 12 | |
PACEB-F4-024 (gold and silver alloy) Gold: 78, 17, 5 Silver: 56, 24, 20 | |
ACEB-F4-025 (gold and silver alloy) Gold: 80, 16, 4 Silver: 56, 22, 22 | |
PACEB-F4-026 (gold and silver alloy) Gold: 80, 15, 5 Silver: 77, 13, 10 | |
PACEB-F4-027 (gold and silver alloy) Gold: 79, 16, 5 Silver: 82, 14, 4 | |
PACEB-F4-028 (gold and silver alloy) Gold: 77, 20, 3 Silver: 89, 7, 4 | |
PACEB-F4-029 (gold and silver alloy) Gold: 82, 12.5, 5.5 Silver: 57, 26, 17 | |
PACEB-F4-030 (gold and silver alloy) Gold: 81, 14, 5 Silver: 52, 26, 22 | |
PACEB-F4-031 (gold and silver alloy) Gold: 77, 17.5, 4.5 Silver *: 68, 16, 16 | |
PACEB-F4-032 (gold and silver alloy) Gold: 77.5, 17.5, 5 Silver *: 60, 19, 21 | |
PACEB-F4-033 (gold and silver alloy) Gold: 81, 17, 2 Silver: 76, 18, 6 | |
PACEB-F4-00102 (gold and silver alloy) Gold: 82.5, 13, 4.5 Silver: 82, 4, 14 | |
PACEB-F4-00103 (gold and silver alloy) Gold: 80, 14, 6 Silver: 78, 12, 10 | |
PACEB-F4-00104 (gold and silver alloy) Gold: 85.5, 11.5, 3 Silver: 83, 10, 7 | |
PACEB-F4-00105 (gold and silver alloy) Gold: 80, 14.5, 5.5 Silver: 60, 15, 25 | |
PACEB-F4-00106 (gold and silver alloy) Gold: 81, 17, 2 Silver: 92, 4, 4 | |
PACEB-F4-00107 (gold and silver alloy) Gold: 72.5, 24.5, 3 Silver *: 74, 6, 20 | |
PACEB-F4-00108 (gold alloy) Gold: 82.5, 12.5, 5 | |
PACEB-F4-00109 (gold alloy) Gold: 80, 13.5, 6.5 | |
PACEB-F4-00110 (silver alloy) Silver *: 41, 37, 22 | |
PACEB-F4-00111 (gold and silver alloy) Gold: 81.5, 14.5, 4 Silver: 58.5, 18.5, 23 | |
PACEB-F4-00112 (gold and silver alloy) Gold: 81, 13.5, 5.5 Silver: 69, 25, 3 (3% As) |
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Number | Au (%) | Ag (%) | Cu (%) | Number | Au (%) | Ag (%) | Cu (%) |
---|---|---|---|---|---|---|---|
002 | 75.5 | 19 | 5.5 | 024 | 78 | 17 | 5 |
003 | 79.5 | 16 | 5.5 | 025 | 80 | 16 | 4 |
004 | 82 | 14.5 | 3.5 | 026 | 80 | 15 | 5 |
006 | 79.5 | 16 | 4.5 | 027 | 79 | 16 | 5 |
007 | 80.5 | 15.5 | 4 | 028 | 77 | 20 | 3 |
008 | 82 | 15 | 3 | 029 | 82 | 12.5 | 5.5 |
009 | 84 | 14.5 | 1.5 | 030 | 81 | 14 | 5 |
010 | 82 | 14.5 | 3.5 | 031 | 77 | 17.5 | 4.5 |
011 | 81.5 | 14 | 4.5 | 032 | 77.5 | 17.5 | 5 |
012 | 80 | 16 | 4 | 033 | 81 | 17 | 2 |
013 | 78 | 19 | 3 | 102 | 82.5 | 13 | 4.5 |
014 | 81 | 14 | 5 | 103 | 80 | 14 | 6 |
015 | 75.5 | 20.5 | 4 | 104 | 85.5 | 11.5 | 3 |
016 | 79.5 | 16 | 4.5 | 105 | 80 | 14.5 | 5.5 |
017 | 78.5 | 16.5 | 5 | 106 | 81 | 17 | 2 |
018 | 75 | 19.5 | 5.5 | 107 | 72.5 | 24.5 | 3 |
019 | 78 | 17 | 5 | 108 | 82.5 | 12.5 | 5 |
020 | 82.5 | 14 | 3.5 | 109 | 80 | 13.5 | 6.5 |
021 | 81.5 | 14.5 | 4 | 111 | 81.5 | 14.5 | 4.5 |
022 | 79 | 15.5 | 5.5 | 112 | 81 | 13.5 | 5.5 |
023 | 82 | 14.5 | 3.5 | Mean value | 80 ± 2.5 | 16 ± 2 | 4 ± 1.5 |
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Gigante, G.E.; Cesareo, R.; Bustamante, A.; Fernandez, A.; Franco, R.; Azeredo, S.; Lopes, R.T. Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao. Heritage 2023, 6, 6268-6290. https://doi.org/10.3390/heritage6090328
Gigante GE, Cesareo R, Bustamante A, Fernandez A, Franco R, Azeredo S, Lopes RT. Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao. Heritage. 2023; 6(9):6268-6290. https://doi.org/10.3390/heritage6090328
Chicago/Turabian StyleGigante, Giovanni E., Roberto Cesareo, Angel Bustamante, Arabel Fernandez, Régulo Franco, Soraia Azeredo, and Ricardo T. Lopes. 2023. "Studies and Considerations on Forty-Three Gold and Silver Nose Ornaments from the Moche Tomb of the Lady of Cao" Heritage 6, no. 9: 6268-6290. https://doi.org/10.3390/heritage6090328