Are you at Hokkaido Univ. now? If you have sufficient amount of the sample for X-ray diffraction analysis, X-ray diffraction method is the best one for solving your question. In the case that the mineral is in a thin section, Raman spectroscopic method may give you any inormation. But I'm not sure whether Raman spectroscopic database has its data or not.

Prof. Akasaka, I'm still in PNG at the moment. I'm writing a paper on the supergene ores collected from the Federal Flag deposit during my PhD course and having some difficulty in explaining the existence of this particular phase. I think it might be a mixture of native copper + copper oxides+ copper hydroxides/copper salts. Please see my PhD thesis copy you have. Many thanks. 

The staff of our department building boundary position of equilibrium of metallic copper and copper sulfide, depending on the pressure and tempepratury. They concluded that at room temperature and normal pressure is always from the existence of equilibrium defects associated with copper deficiency. This deficiency decreases with increasing pressure and tempeature and disappears when seems 400 or 500 C, and I do not remember now what pressure. It was about 30 years ago... Links to their articles to me can not to be found, but samples with a copper content greater than one definitely can not be single phase.

Dear Mr. Noku,

It seems to be native copper with inclusions of Cu sulfides such as covellite and/or minerals from chalcocite to digenite. These supergene minerals form in the lower parts of the gossan of many Cu deposits side-by-side and can easily be determined in polished sections under the EMP or any other device able to do microchemical studies. This is the first step to be done to be sure that no mixture of minerals is present in the specimen. It cause some problems in case of a very small particle size of the mineral inclusions and you might obtain no perfect chemical composition of these minerals but you can definitely exclude a phase like that given in the header of your question. Nano scale mineralogy may be the "last resort". I refer to Fig. 12e and f for constraining the pH-Eh (Dill et al. 2013) Metalliferous duricrusts (“orecretes”) – markers of weathering: A mineralogical and climatic-geomorphological approach to supergene Pb-Zn-Cu-Sb-P mineralization on different parent materials. I can send a copy to you on request. I would like to see an image of the original specimen; in places the morphology of gossan minerals might direct your thoughts in one or the other direction. Then try and have some polished sections prepared. Maybe under the ore microscope you can already take a decision whether it is a homogeneous or heterogeneous natural product.

I wish you all the best for solving this problem.

Best regards

Harald G. Dill

Dear Prof. Dill,

I'm writing a paper on the supergene ores collected from the Federal Flag deposit, Papua New Guinea, during my PhD course and having some trouble explaining the existence of this particular phase. Initially I thought it might be a mixture of native copper + copper oxides+ copper hydroxides/copper salts however, I have not done more analytical work on the mineral apart from the EPMA and mapping. 

If you could kindly send me your 2013 article it would be much appreciated.

Many thanks for the information.

Kind regards,

Shadrach Noku

Dear Mr.  Noku,

please send me a message through RG and I will forward "privately" to you a copy of those studies related to this topic. I recommend to visit the website: www.hgeodill.de under publications; you will find another one published in, e.g., "Geomorphology" there. Let me know in case of further support on this matter.

With best regards

Harald G. Dill

Dear Prof. Dill,

I would like to email you the specimen image including the photomicrograph, mapping and EPMA data for your consideration. Do I have to use your private email address to send you those data?

Kinad regards

Shadrach Noku

Dear Mr. Noku,

make a selection of the most important images which you assess as taking a key position in the interpretation of your minerals the resultant environment. It should be four or so. based upon them we can decide how to proceed and whether we put the train on a private track.

With best regards

Harald G. Dill