Hi Folks,
I have a problem with the nomenclature of the Epidote group minerals.
The principle formular can be written as Ca2(Fe3+,Al)Al2(Si2O7)(SiO4)OOH.
There is an Fe-Endmember, called "Pistacite", containing 1 Fe3+ pfu
(Ps100). There also is a monoclinic Fe-free endmember (Ps00), which is
called "Clinozoisite". So far so good, but what is "Epidote"?
Some papers distinguish between clinozoisite and epidote at a Ps-content of
50, to be consistent with other nomenclatures. Some papers put the line to
Ps33, because optical character changes from positive to negative at that
point. Some even call the entire series from Ps00 to Ps100 "clinozoisite".
Is there an official nomenclature of the epidote group minerals?
Thanx, horst
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Horst Marschall
Mineralogisches Institut
Universitaet Heidelberg
INF 236
69120 Heidelberg
++49-(0)6221-546021
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