Minor Elements and Color Causing Role in Spinel: Multi-Analytical Approaches

Round 1

Reviewer 1 Report

The article presents the results of evaluating the chemical composition that directly affects the color composition in spinel. The paper is very well-written. It just needs a revision of typographical errors or slight misprints (double-check the parenthesis and the repeated spaces). The bibliography presented is complete. Although the paper deserves to be published in a prestigious journal like Minerals, it needs some revisions before it is published.

1.       Line 13: “Natural Natural spinel”. The word natural is repeated.

2.       Is it available the provenance of the studied spinel? Please, add to the paper this information.  

3.       The affiliations shall be indicated according to the journal policies. It can be helpful to compare the affiliation indicated in this paper with the affiliation(s) indicated in any other article published by minerals, MDPI. What is the affiliation of Mr. SAIYASOMBAT

 

I believe that overall, the paper deserves to be published in a prestigious journal like Minerals after the indicated improvements.

Author Response

Dear Reviewer,

We have revised our manuscript and concludes all response to your comment within the attached file. Thank you very much for your support.

With best regards,

 

Author Response File: Author Response.pdf

Reviewer 2 Report

The work is interesting but it should be better focused on heat treatments.

It should be clearly reported the distinction between color causes in natural MgAl2O4 spinel, already studied in the literature, and color modifications induced by heat-treated.

The trace elements (< 0.01 wt%) were not investigated properly and therefore cannot discussed properly. Apart from Co, which may be present as a trace but can influence the color even at such low quantities, most of the chromophore in MgAl2O4 spinel are present as minor elements (1 < wt% < 0.01). Please revise the text accordingly.

A lot of comments and suggestions are included in the annotated text.

The analytical errors are missing in Table 3.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you very much for your support and valuable comment. We have responded as concluded in the attachment. Although, most of your comments are addressed, a few concerns are explained and modified appropriately. Please let me know if you have further suggestion.

With best regards,  

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript is well-designed and detailed study of color in spinel. I recommend accept the manuscript after minor revision:

1) In experimental technique the resolution of Raman spectrometer is not given.

2) The absorption spectra in Fig. 2 have very poor quality. They should be improved.

3) I recommend to replot Fig. 2 in absorption coefficient coordinates.

4) The Raman peak position is given with over-precision. Decimal sign should be omitted because of the spectral  resolution of Raman spectrometer is above than 0.1 cm-1.

5) The authors also can calculate color coordinates from absorption spectra  attributed to different colors (magenta, purple and etc).

Author Response

Dear Reviewer,

Thank you very much indeed for your valuable suggests and constructive comments. We have modified and improve the revised version as concluded in the attachment. Please let us know if you have further suggestion.

With best regards,

Author Response File: Author Response.pdf