Based upon your rather general question the following briefing may be done:

Structure-related bismuth deposits

(1) Ag- Ni-Bi-Co-U veins (Five-Element Association)

(2) Ag- Au-As-Bi-Cu orogenic veins

The major minerals can be

1. native bismuth Bi (100 wt % Bi)

2. bismutinite Bi2S3 (81 wt % Bi) in low- to high-temperature hydrothermal vein deposits, in some gold veins formed at high temperatures, and in recent volcanic exhalation deposits

3.bismite Bi2O3 (98.7 wt % Bi) oxidation product of other Bi minerals

4. eulytine Bi4(SiO4)3 (75 wt % Bi)

There exists a couple of Bi minerals which cannot be addressed without a proper knowledge of the chemical composition and the characteristic mineralogical features that you can find in databases like “mindat.org” on the internet

The epithermal deposits which are reasonable targets for your study are as follows:

1) High sulphidation-type/ quartz alunite-type Au-Ag-Cu deposits

2) Low sulphidation-type/ adularia-type Au-Ag deposits

3) Hot spring Au deposits bound to subaerial siliceous sinter

They are explored and exploited for gold, copper and silver but may also contain Bi as a by-product.

The major type where both elements are associated with each other is given under point 2 and marked in bold-faced letters.

With kind regards H.G.Dill

Such an explicit answer...what else I have to say...thanks to H.G.Dill for such valuable information

Dear Prof. Dill,

Thanks a lot for your reply.

Could you please introduce several papers about it?

Best Regards,

Norouzi

Dear Mrs. Masoumeh,

much of that what I wrote in my post to this thread has been derived from my lessons in economic geology of mineral deposits. I am currently working on topics different from yours. Therefore I can only advice you to consult the review paper DILL, H.G. (2010) The “chessboard” classification scheme of mineral deposits: Mineralogy and geology from aluminum to zirconium.- Earth Science Reviews, 100: 1-420.

With my kind regards

H.G.Dill