Table 2.

Average EMPA data for the studied glaucophane. Chemical formula (in a.p.f.u.) calculated on the basis of 23 oxygen atoms.

Oxide	wt% (n = 35)	σ(n−1)
SiO2	58.45	0.59
TiO2	0.03	0.02
Al2O3	10.54	0.35
FeO	6.45	0.33
Fe2O3	1.79	–
MnO	0.06	0.03
MgO	11.91	0.28
CaO	1.17	0.43
Na2O	6.88	0.22
K2O	0.02	0.02
F	0.19	0.49
O_F_Cl	−0.08	0.01
Total	97.49
Si	7.97
Al	0.03
∑ T site	8.00
Al	1.66
Fe3+	0.18
Ti	0.003
Mg	2.42
Fe2+	0.74
Mn	0.007
∑ C site	5.00
Ca	0.17
Fe2+	0.00
Na	1.83
∑ B site	2.00
Na	0.00
K	0.003
∑ A site	0.003
F	0.08
OH	1.92
Mg/Mg+Fe	0.77