Provenance Studies of a Set of Pick-Up Glass Fragments Found in Portugal and Dated to the 17th Century

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is devoted to multi-analytical study of decorated glass artifacts from two monasteries in Portugal. Authors have applied PIXE, LA-ICP-MS, micro-Raman and UV-Vis spectroscopy. Clear glass base and pigmented glass decorative layers were studied separately.

There are several major remarks to the presented manuscript.

1. The mansucript is lengthy, about 40 pages, and difficult to comprehend. The amount of data is very large. I suggest either to shorten the manuscript considerably or to split it into several papers in series.

2. The concept of substracting the oxides related to colorants to calculate the composition of clear glass base, in my opinion, is incorrect. First, colorants could contain some matrix elements as admixtures. Second, some elements related to colorants (i.e. Fe) could be present in clear glass base.

3. Data on elemental composition of samples should be accompanied by clear indication of method used (PIXE, LA-ICP-MS). Data should be presented with confidence intervals (CI) or relative standart deviations (RSD). Literature data should also be clearly stated as such. For example, Table 1 has no references to method, no CI or RSD.

4. The main conclusions of the article are based on the quantitative composition of glass. This is why the issues of accuracy and reproducibility of the analysis are of paramount importance. It is necessary to indicate which reference materials were used for calibration of PIXE and LA-ICP-MS. Calibration procedures and calculation of sample composition should also be discussed.

(Some) minor remarks.

5. Lengthy tables, such as 1 and 2, shoud be moved to Supplementary information. Some kind of summarising information could be provided in the mansucript instead.

6. There are several geochemical patterns in Fig. 7. What are the criteria to select these particular patterns? Is the difference between them really significant?

7. Fig. 6. Zr-Hf correlation is close to unity. Is it really necessary to use both elements for classification?

 

In my opinion, the manuscript should undergo major revision.

Author Response

Dear Mr./Mrs. Reviewer, thank you very much for all your comments/ suggestions which enriched undoubtedly our work.

Concerning your observations we decided to answer them by following your division:

1. The manuscript is lengthy, about 40 pages, and difficult to comprehend. The amount of data is very large. I suggest either to shorten the manuscript considerably or to split it into several papers in series.

R: In our opinion, by dividing the article into two parts, one of them would end up more "poorer" in terms of originality. Also, the conclusions are supported by all the information as a whole, and to divide the article into two (or more) parts it would turn the individual conclusions less strong. We recognize that the article is very long, but we consider it to be a very complete article on the study of this very complex glass artefacts. We do not know any article which covered all the different characteristics of pick-up glass (compositional characteristics, morphological characteristics and symbolical meaning). Moreover, considering that the subject of this special issue is "The Significance of Things beyond Materiality. Archaeological Glass and Glazes as Archives of Knowledge from the Past" we tried to present and explain the meaning of the data that we can extract from the selected analytical methods.

The structure of this article was very discussed and the division of the work in several different sub-section into the result and discussion section (Base glass, Alkali sources, Silica sources, geochemical patterns, All layers together, Naturally colored, Colored glass layers, Morphological characterization of millefiori fragments, and the summarization section where all the data presented and discussed previously are discussed all together by highlighting the stronger evidences of the proposed provenances) was created to facilitate the comprehensive understanding of this work.

Because it is so complete we are really convinced that this will be a work of reference in different topics.

 

2. The concept of subtracting the oxides related to colorants to calculate the composition of clear glass base, in my opinion, is incorrect. First, colorants could contain some matrix elements as admixtures. Second, some elements related to colorants (i.e. Fe) could be present in clear glass base.

R: We agree that the “subtracting oxides related to colorants” method is not perfect. However, it has been profusely used by other authors such as e.g. Augusta Lima, Marco Veritá and Isabela Biron and was previously used in our recent article (Pulido Valente et al. 2023, published in the Journal of Archaeological Science: Reports - https://doi.org/10.1016/j.jasrep.2023.104228) to distinguish the type of base glass as it has been considered as representative of the original clear glass (at least, the most closer we have)). As we know that Fe₂O₃ can also came from the raw-materials we decided to present the chart of MnO vs. Fe₂O₃ for all clear and colored glass (Fig. 10) where we show that, at least, in all the analyzed red layers the iron oxide was certainly intentionally added to the raw material to facilitate the copper oxide reduction (as it has been pointed out in recipes and treatises of late Medieval and Modern Period).

To uniformize all the glass layers the iron oxide was removed from the “base glass” but it is presented and discussed later on. So, because we do not have any better solution, we decided to use this method to better understand what should be the original composition of clear glass used in the colored glass layers. To be honest, the colored glass has been much less studied than the clear glass, maybe because of this type of issues but, in our opinion, the study of colored glass must to be systematized as happened for clear glass. 

 

3. Data on elemental composition of samples should be accompanied by clear indication of method used (PIXE, LA-ICP-MS). Data should be presented with confidence intervals (CI) or relative standart deviations (RSD). Literature data should also be clearly stated as such. For example, Table 1 has no references to method, no CI or RSD.

R: All the requested information was provided. A table named as “Presentation of the glass composition for the glass material used for the calibration of LA-ICP-MS equipment (N610, N612, CORNA, CORNB, CORND and CORNC). The composition is presented in average (wt% for oxides and µg/g for the elements) as well as the relative standard deviations (RSD) for each referenced glass” will be incorporated in the supplementary material. All the compositional data was acquired by LA-ICP-MS and that information is also clarified. Thank you for your observation.

 

4. The main conclusions of the article are based on the quantitative composition of glass. This is why the issues of accuracy and reproducibility of the analysis are of paramount importance. It is necessary to indicate which reference materials were used for calibration of PIXE and LA-ICP-MS. Calibration procedures and calculation of sample composition should also be discussed.

R: Thank you for your comment, this information was incorporated into the document.

 

(Some) minor remarks.

5. Lengthy tables, such as 1 and 2, should be moved to Supplementary information. Some kind of summarizing information could be provided in the manuscript instead.

R: Thank you for your observation, I will ask to substitute the Tab. 1 and 2 for tables with average, minimum and maximum values of each color and context and send these lengthy tables for supplementary material, as you suggested.

 

6. There are several geochemical patterns in Fig. 7. What are the criteria to select these particular patterns? Is the difference between them really significant?

R: Thak you for your observation. We agree that some geochemical patterns presented in fig. 7 are almost similar to each other. However, for the first 5, some deviations can be observed between Zr and Ce elements and Eu and Ho elements. In addition, the 7^th, 8^th and 9^th patterns are also similar to each other but some deviations can be note between the elements Ti and Nb and Er and Hf. For these last group of patterns, we have some unpublished data (future work) that suggest that they come from different glass production centers (Venice and Holand). This information will be presented and discussed in a future publication and investigation of beads production. For now, we do not have sufficient information that allows us to infer that from PG1 to GP5 belong to the same geological origin due to some patterns deviation, that is why we decided to present them all separated (as a having a probable different origin).

 

7. Fig. 6. Zr-Hf correlation is close to unity. Is it really necessary to use both elements for classification?

R: Zr-Hf correlation has been profusely used by several authors (e.g. I. Coutinho, I. De Raedt, S. Cagno and Ž. Šmit) to discriminate production origins, mainly Venetian/ Antwerp and other provenances (“It is broadly accepted that Venetian glass exhibits the lowest Zr content (< 30 µg g–1), whereas glass production centers of façon-de-Venise display higher levels of these elements [53-55]”). Based on this information, the glass samples that present values compatible with Venetian values were presented: (1) Clear: SCV (364 and 394), (2) Blue: SCV (250, 364, 366 and 394), (3) Red: SCV (235, 250, 275, 329 and 364), (4) Turquoise: SCV_366 and (5) White: SCV (232, 250, 329, 360, 364 and 394), SJT (01 and 09). That is why this fig. was presented.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript ‘Provenance studies of a set of Pick-up glass fragments found in

Portugal and dated to the 17th Century’ written by a team:Francisca Pulido Valente, Inês Coutinho, Teresa Medici, Bernard Gratuze, Luís Alves Cerqueira, Ana Cadena, Márcia Vilarigues is very interesting and concerns important issues related to the history and technology of pick-up technique, specifically of millefiori glass. This topic undoubtedly requires further research, and this article makes an important contribution to that research.

It is logically planned and presented, with a clear abstract and introduction. The only comment about the abstract concerns the use of symbols of various geochemical patterns (GP1, 6 and 7), which should be understandable without reading the entire article.

. It is easy to follow the subsequent stages of work, and the results and conclusions are comprehensive and consistent with respect to the adopted methodology. All figures and tables are justified and necessary. However, in my opinion, there are some issues that need to be clarified. Therefore, the manuscript should be published with minor corrections.

1.       The reference list contains some mistakes. For example - item no. 11 in the bibliography list contains two publications. The description to Fig. 5 contains items that are not in the list at the end of the work. In some items, the order of authors is not correct, etc. In general, there is a certain chaos visible in the literature.

2.       In the caption of table 1 there should be clearly stated that this is a reduced/normalized composition.

3.       Two Figures should be improved.

Fig. 4. The maximum value of Y can be reduced to 0.3 or 0.4. Currently the chart is unreadable.. There are also some errors, e.g.: there are no markings for "pw" (production waste), which is mentioned in the caption; there are some typos, e.g. "comum" should be "common"? The caption should contain information whether the values presented are calculated based on the normalized or unnormalized values. The correlation lines are not visible. I also do not understand the equation: ‘Na2O*+K2O*=0.6 and 0.75’.

Fig. 5. In the legend, the sources of results used in the figure should be linked to the appropriate reference numbers from the reference list at the end of the article. In addition, some references in this figure contain errors, incorrect dates, names, etc. Some characters (e.g. red "x") are visible that are not described in the legend..

Fig. 13. The lines of SCV_357 and 365 should be more distinguishable from each other

Author Response

Dear Mr./Mrs. reviewer, thank you very much for all your comments/ suggestions which enriched undoubtedly our work and let us look into some subjects in other ways. We really appreciated your kind contribution and compliments.

Concerning your observations we decided to answer them by following your division:

The manuscript ‘Provenance studies of a set of Pick-up glass fragments found in Portugal and dated to the 17th Century’ written by a team: Francisca Pulido Valente, Inês Coutinho, Teresa Medici, Bernard Gratuze, Luís Alves Cerqueira, Ana Cadena, Márcia Vilarigues is very interesting and concerns important issues related to the history and technology of pick-up technique, specifically of millefiori glass. This topic undoubtedly requires further research, and this article makes an important contribution to that research.

It is logically planned and presented, with a clear abstract and introduction. The only comment about the abstract concerns the use of symbols of various geochemical patterns (GP1, 6 and 7), which should be understandable without reading the entire article. R: Thank you for your observation, it was corrected.

It is easy to follow the subsequent stages of work, and the results and conclusions are comprehensive and consistent with respect to the adopted methodology. All figures and tables are justified and necessary. However, in my opinion, there are some issues that need to be clarified. Therefore, the manuscript should be published with minor corrections.

1. 1.       The reference list contains some mistakes. For example - item no. 11 in the bibliography list contains two publications. R: Thank you for your observation, it was an error, the second reference of 11th point is the one that is in 70th. It is already corrected.

The description to Fig. 5 contains items that are not in the list at the end of the work. In some items, the order of authors is not correct, etc. In general, there is a certain chaos visible in the literature. R: You are right, the data is already organized. Thank you for your observation.

2. 2.       In the caption of table 1 there should be clearly stated that this is a reduced/normalized composition be. R: Thank you for your observation, this information was added to Tab.1.
3. 3.       Two Figures should be improved.

Fig. 4. The maximum value of Y can be reduced to 0.3 or 0.4. Currently the chart is unreadable. There are also some errors, e.g.: there are no markings for "pw" (production waste), which is mentioned in the caption; there are some typos, e.g. "comum" should be "common"? The caption should contain information whether the values presented are calculated based on the normalized or unnormalized values. The correlation lines are not visible. I also do not understand the equation: ‘Na2O*+K2O*=0.6 and 0.75’. R: Thank you for your observation. The image was improved, and the legend was adapted from a previous paper and “pw” does not belong from here. The value 0.6 has been attributed to untreated ashes while 0.75 has been attributed to treated ashes.

Fig. 5. In the legend, the sources of results used in the figure should be linked to the appropriate reference numbers from the reference list at the end of the article. In addition, some references in this figure contain errors, incorrect dates, names, etc. Some characters (e.g. red "x") are visible that are not described in the legend. R: Thank you for your observation. Fig. 5 was improved and the references were corrected.

Fig. 13. The lines of SCV_357 and 365 should be more distinguishable from each other. R: Thank you for your observation, the image was improved.

 

Reviewer 3 Report

Comments and Suggestions for Authors

Comments for review of Heritage paper N. 3144030 – Aug 04 2034.                         

General comment:

This work is particularly interesting because there is a lack of analytical data and in-depth studies in the literature on these types of glass and the period to which they belong. This study is original and comprehensively addresses all the typical aspects of glass analysis using multiple and suitable analytical techniques. The bibliography is extensive and relevant. The work is well-organized and well-written.

 In my opinion, this manuscript can be published after incorporating some minor revisions that I suggest and justify in my comments.

 

Specific comments: 

1.    Introduction 

1.1   Archaeological context and material

Please specify if all the glass samples studied are opaque. If  there are some transparent or translucent, please indicate  in Tables 1 or 2.

 

2.  Methodology 

2.2. UV-Vis Absorbance and Reflectance Spectroscopy

- The procedure of the measurements is not specified. There are no information about the diameter of the optical fiber, whether the scattered light is collected with the fiber in direct contact and perpendicular with the sample or at a certain (small) distance, and In the text you specified that  "The operational range is 200 to 800 nm", while the spectral range in  the figures 12-17 are from 350 to 1100 nm. Please justify this discrepancy.

 

3. Results and Discussion

3.1 Base glass 

Table 1 and 2: Please ensure that the oxide formulas are repeated at the top of the columns on each new page of the table, to facilitate its reading.

Table 2:  In this table  antimony is not present.  On line 766 (3.3.2.6. WHITE) you stated that   calcium antimonate was not detected in the analysed samples. Even if you hypothesised a very low amount of antimony, is quite unusual to exclude antimony (Sb) from the elemental analysis when a white opaque sample is present. Moreover  (, in 3.1 Section, lines 223-224, it is stated that “…opacifiers (including antimony and tin), and other related elements […] were subtracted from the main composition …”.  Which antimony was subtracted? Furthermore, the quantity of heavy metals, including antimony, is useful in determining whether a glass is recycled.

 Lines 457-460: The sentence “Interesting to note, when gathering the information of Eu/Eu* values … show the GP7” seems syntactically incorrect and therefore rather incomprehensible. Please rearrange it clearly.                                                                                                                                               

 

 

3.3.1. Naturally colored glass

 Lines 535-536: “Manganese oxide […] can impart a deep purple hue”.                                                    

It should be specified that the purple hue is due to the chromophore Mn³⁺ and therefore to the oxide Mn₂O₃, deriving from the manganese compound added to the  glass batch, probably pyrolusite (MnO₂).

In addition,  to complete the mechanism of glass decolourising it is appropriate to observe that the purple hue (given by the residual Mn³⁺ after the oxidation of Fe²⁺) is complementary to the yellow hue of Fe³⁺, thus producing an achromatic hue (white or gray).

3.3.2. Colored glass layers

3.3.2.1. BLUE

- Fig. 13: I have some doubts about attributing the shoulder band at about 450 nm (dotted line spectrum) to Mn³⁺, which typically corresponds to a broad band with a max at 490 nm. The overlap of this band with the initial rising part of the Co²⁺ spectrum causes its rightward shift. Consequently, the narrow band that was attributed to Mn³⁺ seems more likely to correspond to one of the Fe³⁺ bands.

The same comment  for the statement on line 629. 

-   Lines 620-621: Considering that a different sample composition can cause slight variations in the geometry of the ligand field around a chromophore ion, and thus a little shift in its characteristic bands, the typical three bands of Co²⁺ in tetrahedral coordination within silica-soda glass appear at 535, 595, and 640 nm. 

- Lines 631-632: The indications about the origin of the cobalt mineral would be more clear analysing the plot of  As vs. Co (as well as  of Ni, Zn and Bi vs. Co), that can also distinguish the subgroups. But I understand that it might weigh down this already very long paper. I leave the choiche to the authors.

 

3.3.2.2. GREEN 

- Fig. 14.

 Caption: “…manganese (Fe^2+/3+) ions”.

This is the first of some mistakes in the caption, probably due to oversights. The Mn³⁺ band is not at all evident, as well as the Fe³⁺ band, even if the latter is probably present, but covered by the matrix spectrum. So I think, also on the basis of the concentration values ​​(Table 2) and the inset of Fig. 13, that the second part of the caption of Fig. 13 should be modified as follows: "... discernible influence of Cobalt (Co²⁺), iron (Fe²⁺) and copper (Cu²⁺) ions within the glass matrix."

 

-   I am quite surprised that such a small amount of cobalt oxide (164 ppm) produces such a strong spectrum, also considering that the Co²⁺ ion is the most powerful glass colorant. Since I have no reason to doubt the measurements, maybe it would be suitable to highlight this finding, provided the measurements are verified. 

 

-   The short rise at the right end of the spectrum is not due to Fe²⁺ is probably due to an experimental artifact or is part of the increased noise at this spectral end. The Fe²⁺ band is at ca. 1050-1100 nm and is very broad, with a left tail starting around 700 nm. In this spectrum it overlaps that of Cu²⁺ and is therefore not very evident. The arrow indicating Fe²⁺ should be placed vertically at ca. 1050 nm.

 

3.3.2.3. PURPLE

 Fig. 15:

In my opinion no chromophore is clearly discernible in this spectrum. The elements that significantly influence the colour can be deduced from their concentrations (Table 2). It can only be said that the spectrum is not incompatible with the presence of Mn, Co, Fe and Cu and it can be considered an envelope of the spectra of the respective ions, where the presence of Mn³⁺ and Cu²⁺ is more apparent.

 

3.3.2.4. Red

-    (line 679):  Please write Red in capital letters, as for the other colours.

-   Fig. 16, caption: You wrote “ … the discernible influence divalent copper” . Please correct as:  “the discernible influence of monovalent (Cu⁺) and metallic (Cu⁰) copper”.

-  In the inset: instead of Cu, write  Cu⁰.

Comments on the Quality of English Language

I am not a native English speaker, but the language of this manuscript seems good to me.

Author Response

Dear Mr./Mrs. Reviewer, thank you very much for all your comments/ suggestions which enriched undoubtedly our work and let us look into some subjects in other ways. We really appreciated your kind contribution and compliments.

Concerning your observations we decided to answer them by following your division:

1. Introduction 

1.1   Archaeological context and material

Please specify if all the glass samples studied are opaque. If there are some transparent or translucent, please indicate in Tables 1 or 2. R: Dear reviewer, thank you for your observation. Now, the information on tables 1 and 2 are more complete.

 

2. Methodology 

2.2. UV-Vis Absorbance and Reflectance Spectroscopy

- The procedure of the measurements is not specified. There are no information about the diameter of the optical fiber, whether the scattered light is collected with the fiber in direct contact and perpendicular with the sample or at a certain (small) distance, and In the text you specified that "The operational range is 200 to 800 nm", while the spectral range in the figures 12-17 are from 350 to 1100 nm. Please justify this discrepancy. R: Dear reviewer, thank you for your comment. The diameter of the optical fibre is 100 µm and the scattered light was collected with the fibre in direct contact with the sample. We start this experiment with a less powerful equipment, and I forgot to change the values of the operational range. Your corrections were introduced in the document.

 

3. Results and Discussion

3.1 Base glass 

Table 1 and 2: Please ensure that the oxide formulas are repeated at the top of the columns on each new page of the table, to facilitate its reading. R: Thank you for your observation, your suggestion was followed.

Table 2:  In this table antimony is not present.  On line 766 (3.3.2.6. WHITE) you stated that   calcium antimonate was not detected in the analysed samples. Even if you hypothesised a very low amount of antimony, is quite unusual to exclude antimony (Sb) from the elemental analysis when a white opaque sample is present. Moreover (, in 3.1 Section, lines 223-224, it is stated that “…opacifiers (including antimony and tin), and other related elements […] were subtracted from the main composition …”.  Which antimony was subtracted? Furthermore, the quantity of heavy metals, including antimony, is useful in determining whether a glass is recycled. R: Thank you for your observations, the antimony value was added to the Tab. 2.

Lines 457-460: The sentence “Interesting to note, when gathering the information of Eu/Eu* values … show the GP7” seems syntactically incorrect and therefore rather incomprehensible. Please rearrange it clearly. R: Thank you for your observation. Eu/Eu* values are related with chondrite normalization while GP are related with upper Earth normalization. Here we are relating all the information related with silica sources, we trayed to clarify this information.

 

 

3.3.1. Naturally colored glass

 Lines 535-536: “Manganese oxide […] can impart a deep purple hue”.                                                    

It should be specified that the purple hue is due to the chromophore Mn³⁺ and therefore to the oxide Mn₂O₃, deriving from the manganese compound added to the glass batch, probably pyrolusite (MnO₂). In addition, to complete the mechanism of glass decolourising it is appropriate to observe that the purple hue (given by the residual Mn³⁺ after the oxidation of Fe²⁺) is complementary to the yellow hue of Fe³⁺, thus producing an achromatic hue (white or gray). R: Thank you for your comment. This information was added to the document.

 

3.3.2. Colored glass layers

3.3.2.1. BLUE

- Fig. 13: I have some doubts about attributing the shoulder band at about 450 nm (dotted line spectrum) to Mn³⁺, which typically corresponds to a broad band with a max at 490 nm. The overlap of this band with the initial rising part of the Co²⁺ spectrum causes its rightward shift. Consequently, the narrow band that was attributed to Mn³⁺ seems more likely to correspond to one of the Fe³⁺ bands. R: Thank you for your correction. After your observation we agree with your opinion.

The same comment  for the statement on line 629. 

-   Lines 620-621: Considering that a different sample composition can cause slight variations in the geometry of the ligand field around a chromophore ion, and thus a little shift in its characteristic bands, the typical three bands of Co²⁺ in tetrahedral coordination within silica-soda glass appear at 535, 595, and 640 nm. R: Your comment was incorporated in this work. Thank you for the observation.

- Lines 631-632: The indications about the origin of the cobalt mineral would be more clear analysing the plot of  As vs. Co (as well as  of Ni, Zn and Bi vs. Co), that can also distinguish the subgroups. But I understand that it might weigh down this already very long paper. I leave the choiche to the authors. R: Dear reviewer, thank you very much for your suggestion of improvement. This Work is really large, so we decided to keep it as it is. However, for the next work we will incorporate your observation.

3.3.2.2. GREEN 

- Fig. 14. Caption: “…manganese (Fe^2+/3+) ions”. – R: Modified, thank you for the observation.

This is the first of some mistakes in the caption, probably due to oversights. The Mn³⁺ band is not at all evident, as well as the Fe³⁺ band, even if the latter is probably present, but covered by the matrix spectrum. So I think, also on the basis of the concentration values ​​(Table 2) and the inset of Fig. 13, that the second part of the caption of Fig. 13 should be modified as follows: "... discernible influence of Cobalt (Co²⁺), iron (Fe²⁺) and copper (Cu²⁺) ions within the glass matrix." – R: Modified, thank you for the observation.

- I am quite surprised that such a small amount of cobalt oxide (164 ppm) produces such a strong spectrum, also considering that the Co²⁺ ion is the most powerful glass colorant. Since I have no reason to doubt the measurements, maybe it would be suitable to highlight this finding, provided the measurements are verified. R: Thank you for your observation, this observation was also noted in some clear façon-de-Venise glass objects (almost transparent) published by Inês Coutinho and co-authors (2016 - https://doi.org/10.1016/j.jasrep.2016.03.019) and presented in Fig. 10 of its work (CoO values were always lower than 60 ppm). For this paper, all the spectrums were measured, at least three times and in all we get the triple band associated with Co²⁺ ion.

- The short rise at the right end of the spectrum is not due to Fe²⁺ is probably due to an experimental artifact or is part of the increased noise at this spectral end. The Fe²⁺ band is at ca. 1050-1100 nm and is very broad, with a left tail starting around 700 nm. In this spectrum it overlaps that of Cu²⁺ and is therefore not very evident. The arrow indicating Fe²⁺ should be placed vertically at ca. 1050 nm. R: The iron was removed from the image. Thank you for your observation.

3.3.2.3. PURPLE

Fig. 15: In my opinion no chromophore is clearly discernible in this spectrum. The elements that significantly influence the colour can be deduced from their concentrations (Table 2). It can only be said that the spectrum is not incompatible with the presence of Mn, Co, Fe and Cu and it can be considered an envelope of the spectra of the respective ions, where the presence of Mn³⁺ and Cu²⁺ is more apparent. R: Thank you for your observation, your explanation was incorporated into the document.

3.3.2.4. Red

- (line 679):  Please write Red in capital letters, as for the other colours. – R: Thank you for your observation.

-   Fig. 16, caption: You wrote “… the discernible influence divalent copper”. Please correct as: “the discernible influence of monovalent (Cu⁺) and metallic (Cu⁰) copper”. R: It was corrected, thank you for your observation.

-  In the inset: instead of Cu, write Cu⁰. R: It was corrected, thank you for your observation.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Authors have provided a revised version of the manuscript. Some reviewer's remarks were addressed in the revised version, some were not. I would make some comments according to the original numeration form the first review.

1. Authors insist that the paper should be published without shortening or splitting, despite agreeing on the point that the paper is of considerable length. I prefer to leave to the Editor the decision on whether such paper length is suitable for publication.

2. In my opinion, possible pitfalls of "oxide substraction" should be discussed in the paper. Authors have discussed this matter in the responce, but it should be incorporated into the text itself.

3,4,5 - Authors have made necessary additions and corrections.

6. In my opinion, it is better to remove the discussion of "geochemical patterns" due to the absence of qunatutative criteria to distinguish one pattern from another one. Such description as, for example, "some deviations can be noted" or "patterns ... are almost similar" is not strict enough to use as the guidelines for future research. Authors have mentioned plans to investigate this approach in more detail. It is better to leave this data for future publication.

7. It is still not clear, why data on Hf concentration is necessary alongside Zr data, because there's almost 100% correlation between these two elements. I understand that Zr concentration is a useful marker, but what extra information do we get when it is accompanied by Hf data? Some explanation should be given in the text.

In my opinion, remarks 2,6,7 require minor revisions. Remark 1 is up to the judgement of Editor.

Author Response

Dear Mr./Mrs. reviewer_1, thank you very much for all your considerations we believe that they are important and improve the value of our article.

Concerning your observations we decided to answer them by following your division:

1. Authors insist that the paper should be published without shortening or splitting, despite agreeing on the point that the paper is of considerable length. I prefer to leave to the Editor the decision on whether such paper length is suitable for publication.

R.: Thank you for your appreciation, we agree that this work is very long, but we consider it to be a very complete article on this complex subject. Moreover, considering that the subject of this special issue is: "The Significance of Things beyond Materiality. Archaeological Glass and Glazes as Archives of Knowledge from the Past" we tried to present and explain the meaning of the data that we can extract from the selected analytical methods.   

 

2. In my opinion, possible pitfalls of "oxide substraction" should be discussed in the paper. Authors have discussed this matter in the responce, but it should be incorporated into the text itself.

R.: Thank you for your observation, this discussion was added to the document (green color).

 

6. In my opinion, it is better to remove the discussion of "geochemical patterns" due to the absence of quantitative criteria to distinguish one pattern from another one. Such description as, for example, "some deviations can be noted" or "patterns ... are almost similar" is not strict enough to use as the guidelines for future research. Authors have mentioned plans to investigate this approach in more detail. It is better to leave this data for future publication.

R.: Thank you for your comment, after a discussion with all the authors of this article, we have reduced the number of GP, from 9 to 4. In our opinion, as this paper is also a provenance study (which we believe is the strongest part), we really wanted to include the geochemical patterns section. This is an innovative investigation of the late medieval and early modern period, as the presentation of GP in the literature is really rare.

This new division was made based on different graphs (e.g. Y/Zr vs Nb/Zr), using the normalized values for the upper crust of the Earth, like this one, where we can distinguish the different GPs.

We hope that, with these modifications, you are able to change your opinion.

 

7. It is still not clear, why data on Hf concentration is necessary alongside Zr data, because there's almost 100% correlation between these two elements. I understand that Zr concentration is a useful marker, but what extra information do we get when it is accompanied by Hf data? Some explanation should be given in the text.

R.: These two elements (Zr and Hf) are usually associated with felsic igneous rocks and are frequently used to distinguish different crustal processes because, while they are similar crustal incompatibilities elements, they are quite stable and resilient to chemical and mechanical destruction. That is why Hf was selected to be presented alongside Zr. This information was incorporated to the article (green color). Thank you for your observation.