Russia: Astrophyllite Syenite
Collection:
Greenland
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Fact sheet

Russia: Astrophyllite Syenite

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

Additional images
 
  • Width 6 cm
  • Width 2 cm
  • Width 2 cm
  • Width 2 cm
  • Width 6 cm
Map
 
67.636023, 33.879089
Description:
Mount Eveslogchorr, Khibina Massif, Kola Peninsula, Murmansk, Russia
About this collection
 
Greenland

The Ilimaussaq alkaline complex is the type locality for agpaitic nepheline syenites and represents an enormous concentration of rare elements, notably Li, Be, Nb, Zr, REE, Y, Th and U. Around 220 mineral species have been identified. We can't identify all the minerals present in these samples. Email us at virtual-microscope@open.ac.uk if you can help.

Note we have recently expanded the collection to include other syenite complexes worldwide.

See also Alex Strekeisen's great website for more information on syenite complexes.

Sample details

Collection: Greenland
Type
igneous
Category
Alkaline Suite
Rock-forming mineral
astrophyllite
eudialyte
aegirine
albite
microcline
nepheline
Accessory minerals
lamprophyllite
loparite-(ce)
rosenbuschite
melilite
Category guide  
Category Guide
Title
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
Description
Refers to any word or phrase that appears anywhere in the descriptions of the specimens
Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Timescale
Selecting one or more period, for example 'Jurassic'.
Theme
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
Category
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
Owner
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample:

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