Weathered Cortex of Eluvial–Deluvial Jadeite Jade from Myanmar: Its Features, Formation Mechanism, and Implications

Round 1

Reviewer 1 Report

The manuscript minerals-1742919 “Weathered Cortex of Eluvial-Deluvial Jadeite Jade from Myanmar: Its Features, Formation Mechanism, and Implications” is a fundamental study of the weathered cortex of the jadeite. Discussions of the available data include critical notes because results are limited to two methods, namely optical microscopy and XRD. There are a lot of areas where I think the authors must reconsider structure and content of the manuscript. Therefore, although the paper's subject is in line with the goals of Minerals, I recommend an extended major revision of the manuscript.

 

Major comments.

1. The manuscript needs to be reorganized. The section “Sample characteristic” is part of the results. Results and methods must necessarily be separated. Discussions and conclusions have to be also divided into two sections. The structure of the manuscript should contain the following sections: 1. Introduction, 2. Geologic Background, 3. Material and Methods, 4. Results (including subsections), 5. Discussions (including subsections), 6. Conclusions.

2. The main points of this study should be more discussed by exemplifying similar studies from other parts of the world. In other words, the authors should justify their conclusions through comparing their results with others’ works, with more emphasis on the similarities and differences of their findings with those works. In general, this is a problem which is present throughout the discussion chapter. The authors should give more credit to others’ works and discuss their findings in the context of previous work. A major revision to the discussion chapter is thus recommended.

3. The abstract should be as essential and informative as possible. Lines 14-16 can be shortened. The number of samples is not required.

4. A geological section or petrographic column is required to demonstrate the area's geological structure. It can be added to Figure 1 or 2.

5. The positions where samples were collected must be marked in Figure 2.

6. Why need a table with a description of each sample? If authors wish to demonstrate this, they can show it in the supplementary materials.

7. Structural features of grains such as size, shape, and distribution should be added to the sample characteristics.

8. Each research method must be described in detail.

9. How were clay minerals identified? It is not described in the methods. How is kaolinite different from halloysite? Has the clay fraction been prepared? What about other clay minerals (e.g. smectites)?

10. What is the chemical composition of the main minerals? How were they defined? Optical microscopy and XRD alone are insufficient for reliable identification of minerals and even more so for explaining their growth in open cavities. Scanning electron microscopy of cortex minerals is required to confirm discussions and conclusions.

11. Line 146-149. The chemical composition of what? Bulk samples or individual minerals? Spot 10 µm does not allow one to judge the bulk composition of the sample due to heterogeneity. How were samples prepared for EPMA?

12. Why was the chemical composition determined? In the results, data on the chemical composition are not described.

13. Conclusions must be added.

 

Minor comments:

14. Line 47-53. Too long sentence. Please divide this thesis into several sentences.

15. Figure 1. Add an overview scheme of the study area.

16. Line 71-73 and everywhere. Use standard references design according to MDPI.

 

17. Figure 2. Add the geographic position of the photo (you can use the diagrams in Figure 1). Add “Yellow, red, and dark sub-layers” markers to figure 2. Add a linear scale.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The paper lacks important information about the data analysis:

In Figure 6 you present powder diffraction data and state "In addition, they all con-163tained unknown impurity peaks, for which there is no specific mineral match; however, 164the peaks indicate that these substances are clay minerals and Fe-bearing colloidal miner-165als (Figure 6). These clay minerals were determined to be kaolinite and halloysite using 166an X-ray single crystal diffractometer"

-> You have to present a) Rietveld refinements of the powder patterns.
b) If you have single crystal data you have to provide the R_1 values, a list of total and of unique reflections, the sigma cutoff for |F(hkl)| weighing, and the hkl-files and res-files as supplement.
As you present it - you only make an unsupported statement - from Fig 6 one can not confirm your statement and the rather important single crystal data are not provided at all.

 

Further: The study is quite incomplete. Missing is

1) SEM + SEM-EDS or EPMA analysis of the cracks and weathering products

2) Raman and or IR spectroscopy

Finally, the English style needs much improvement. I stopped checking at some point but here are a few comments just on the abstract:

Myanmar is the main country that produces high-quality jadeite jade in the world today, 10

-> Change to: ‘Myanmar is the principal provider of high-quality…’

‘.. including so called primary and ….’


‘ often with soil luster and a fansha appearance’

-> what is a ‘a fansha appearance’?

 

The topic is interesting and I like your introduction

I regret to say that in the present state the paper cannot be accepted. You need to present your data in more detail and complement them by further analysis with SEM + SEM-EDS as the minimum.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I have re-read the manuscript Weathered Cortex of Eluvial-Deluvial Jadeite Jade from Myanmar: Its Features, Formation Mechanism, and Implications by Xiangyu Zhang et al. as well as the author’s responses to initial review. The authors have done a commendable job making all the recommended changes and this has strengthened the manuscript. The various small changes throughout the manuscript have clarified a number of points and make the manuscript more coherent. All of this has been done without changing any of the scientific content. As such, I believe the manuscript is now (nearly) ready for publication in Minerals. I recommend doing a careful proofreading of the text again.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors revised the manuscript and present powder XRD data of smectites retrieved from the weathered jade. They also added microchemical analyses. Overall the paper is now acceptable.

I note that the lowest angle smectite base line reflection in the powder diffractogram is not identified - this should be added. Also, the identification of gibbsite is based on the composition - however,Al(OH)3 is polymorph and it would be good if the structure were confirmed - yet, this is an optional addition to this paper.

English wording needs to be improved!

Author Response

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Author Response File: Author Response.docx