Russia: Astrophyllite Syenite
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Fact sheet
Description: 

The astrophyllite deposit from which this sample came is located on the southern slope of Mount Eveslogchorr, south of Murmansk. It is related to zones of albitization of gneissose foyaite and aegirine-nepheline-microcline veins cutting foyaite. The astrophyllite content of the veins and albitites is very variable, from 10 up to 80 vol.%. The veins are 0.5 cm to 7 metres wide and are observed for 10–150 metres along strike. 

The astrophyllite is found in the central parts of the veins as radiating, parallel-columnar, sheaf-like and large-lamellar aggregates of bronze-brown, golden-yellow, greenish-brown and dark brown flattened-prismatic crystals. It occurs in association with aegirine, eudialyte, rinkite, sodalite, cancrinite, loparite-(Ce) and pyrochlore.

Rotation 1 - twinned microcline K(AlSi3O8)
Rotation 2 - melilite CaNaAl(Si2O7) with albite, three altered nepheline crystals and a small aegirine lath
Rotation 3 - rosenbuschite Na6Ca6Zr3Ti(Si2O7)4O2F6
Rotation 4 - natrolite Na2Al2Si3O10·2H2O replacing nepheline 
Rotation 5 - astrophyllite (Na,Mn2+)3(Sr,Na)2(Ti,Fe3+)3(Si2O7)2O2(OH,O,F)2
Rotation 6 - pink eudialyte Na15Ca6(Fe2+,Mn2+)3Zr3[Si25O73](O,OH,H2O)3(OH,Cl)2
Rotation 7 - basal sections of aegirine NaFe3+Si2O6
Rotation 8 - altered nepheline (Na,K)AlSiO4
Rotation 9 - lamprophyllite (Na,Mn2+)3(Sr,Na)2(Ti,Fe3+)3(Si2O7)2O2(OH,O,F)2
Rotation 10 - lamprophyllite (Na,Mn2+)3(Sr,Na)2(Ti,Fe3+)3(Si2O7)2O2(OH,O,F)2
Rotation 11 - loparite-(Ce) (Na,Ce,Ca,Sr,Th)(Ti,Nb,Fe)O3

In Place
In Time
Location description: 
Mount Eveslogchorr, Khibina Massif, Kola Peninsula, Murmansk, Russia
Accuracy:
Timescale:
Not known
Ma = Millions of years ago
In Focus
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Type:
Type: 
igneous
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