Try the attached spreadsheet. It works like this: you have to insert microprobe compositions (either as wt% elements or as wt% oxides, all the analyses expressed in the same way) in worksheet "analyses", and then run Macro1 from the similarly named worksheet. The analyses have to be inserted rather with command "paste special - values" than simply paste. I would appreciate any feedback or questions.

On the other hand, apparent high silica does not indicate by itself metamictization, as it can have a lot of other causes, including systematic errors in silica determination.

Dear Mr. Gavril

I had followed methods of Armbruster et al., 2006 following procedures of Bonazzi et al., 2009 (Si-subtraction) for part metamict epidote group minerals. Senus stricto the minerals are Allanite sub-group with Ce-dominant. My probe data is indicating partial metamictization, Th (2-5%) with La (3-5%); Ce (8-12%). Because of these alteration, I was trying to follow the latter 2009 literature by subtraction Si-excess and normalizing on basis of 8 cations. Somewhere i got confused and is not able to progress. Could you guide me with the abbrevations you have used in the spreadsheet. It appears to be robust one for epidote. I appreciate you help and looking forward for further suggestions. I am attaching the 2009 paper for your reference as well. If any modification to this technique, kindly refer the same. 

It's for sure not password protected - the problem might be with the security settings of your Excel version, which noticed that it contains a macro and disabled it. So you have to enable the macro. For further feed-back please use my e-mail [email protected]. If you feel like, you could also send me the analyses so I can test how it works myself - the spreadsheet is rather old and rarely employed, but it's supposed to work. Depending on your analyses, some other elements might be required for the recalculations.

I have posted my spreadsheet in the given mail id. There are 4 sheets each following different methodologies. It is self-explanatory from the title of the sheets itself. Last one is "Sheet1" which follows the procedure (partially) from Bonazzi et al., 2009. Thanks and let me know the feedback. 

Thank You Mr. Anicet for the publication. It was really informative. I may ask your guidance while dealing with the soil samples and clay adsorption patterns of REE in my study area.

Thanks Mr. Anicet for the guidance

You did not mention the composition of your epidote. Metamictization generally does not occur in common epidotes; in allanite it can.

I have analysed many epidotes and, like you, noted slightly higher Si pfu when recast on 13 (O, OH) basis. May be there is overestimation of SiO2. In their latest Introduction to Rock-Forming Minerals (2013), DHZ have recast epidotes on 12.5 (O,OH).

Cheers, Qasim. 

Thanks you Mr. Jan for your suggestion.