All,
I made a typo on the formula which is corrected below. The wt % were OK.
Eric
>Dr Liu and all,
> The only other sheet silicate resembling muscovite with high K and Al
>that I can think of is zussmanite, but it has far less K. Zeolites,
>osumilite group minerals, feldspathoids and other micas don't seem to fit
>very well. However, the mineral lithosite, K6Al4Si8O25.2H2O, fits pretty
>closely chemically. If this formula is correct, it ideally has (wt %)
>SiO2 47.91,
>Al2O3 20.33, K2O 28.17, H2O 3.59 (cf. Am. Min. 69, 210-215, 1984 for a
>citation). It is worth getting optical and XRD data on your sample to
>confirm or rule out this obscure phase..
>Eric
>
>
>
>>Dear sirs,
>>A mineral which is extremely rich in potassium is found in two rocks from
>>greenschist belt.It looks like mica under thin section. The coexisting
>>minerals are actinolite, epidote, muscovite, albite and qtz. Some EPMA
>>analysis results are shown as following:
>>
>> No. SiO2 TiO2 Al2O3 FeO MnO MgO CaO Na2O
>>K2O Cr2O3 Total
>>
>> 1 45.401 0.232 20.169 0.000 0.000 2.525 0.166 0.129
>>24.796 0.049 93.467
>> 2 47.237 0.135 20.387 0.000 0.000 2.650 0.067 0.122
>>24.809 0.059 95.466
>> 3 46.899 0.217 21.157 0.000 0.000 2.541 0.071 0.115
>>24.579 0.049 95.628
>>I have checked for several possibilities but failed. Could anybody tell me
>>what is could be ?
>>
>>Thanks.
>>
>>R. Liu
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