General Information
|
Chemical Formula: |
(K,Na)3(Fe++,Mn)6(Nb,Ti)2[Si8O24](O,OH,F)7 |
Composition: |
Molecular Weight = 1,345.90 gm) |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Empirical Formula: |
K2.5Na0.5Fe2+5Mn2+Nb1.8Ti0.2Si8O28OH2F |
Environment: |
Flakes in an albite-arfvedsonite paragneiss. |
IMA Status: |
Approved IMA 1964 |
Locality: |
Ten Mile Lake, Seal Lake area, Labrador, NF, Canada. |
Name Origin: |
Named for the niobium content and foliated character common to the astrophyllite group. |
|
Classification
|
Dana Class: |
69.1.1.4 (69)Inosilicate Chains with Side Branches or Loops |
|
(69.1)with (P=2, and N=4, 2 branches) |
|
(69.1.1)Astrophyllite group |
Strunz Class: |
VIII/G.12-80 VIII - Silicates |
|
VIII/G - Intermediate between chain- and layered silicates |
|
VIII/G.12 - Astrophyllite- Kupletskite group |
|
Crystallography
|
Axial Ratios: |
a:b:c =0.4537:1:0.9814 |
Cell Dimensions: |
a = 5.391, b = 11.88, c = 11.66, Z = 1; alpha = 113.1ø, beta = 94.5ø, gamma = 103.1ø V = 666.95 Den(Calc)= 3.35 |
Crystal System: |
Triclinic Space Group: P1,P1- |
X Ray Diffraction: |
By Intensity(I/Io): 3.506(1) 10.52(0.9) 2.778(0.8) |
|
Physical Properties
|
Cleavage: |
[001] Perfect |
Color: |
brown. |
Density: |
3.42 |
Diaphaniety: |
Translucent to Opaque |
Habits: |
Foliated - Two dimensional platy forms., Flakes - Flat, thin crystals or aggregates., |
Hardness: |
3-4 - Calcite-Fluorite |
Luster: |
Vitreous - Adamantine |
|
Optical Properties
|
Optical Data: |
Biaxial (-), a=1.724, b=1.76, g=1.772, bire=0.0480, 2V(Calc)=58, 2V(Meas)=60. |
|
Other Information
|
References: |
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990) |
See Also: |
Links to other databases for Niobophyllite :
1 -Athena Mineralogy
2 - EUROmin Project
3 -MinDat.org Location Data
4 -MinMax
5 -École des Mines de Paris
Search for Niobophyllite using:
[ALTAVISTA]
[All-The-Web]
[EXCITE]
[GO.COM]
[GOOGLE]
[Ixquick]
[LYCOS]
[LookSmart]
[MAMMA]
[MSN.COM]
[NORTHERN LIGHT]
[YAHOO]
Visit our Advertisers for Niobophyllite :
The Arkenstone Fine Minerals
John Betts Fine Minerals
Dakota Matrix Minerals
Excalibur Mineral Co.
Exceptional Minerals
Fabre Minerals
OsoSoft Minerals
Rare Minerals
Tsumeb Minerals
Dan Weinrich Fine Minerals
Ask about Niobophyllite here :
Mindat.org's Discussion Groups
Mindat.org's Collecting Discussion Group
Mindat.org's General Discussion Group
Mindat.org's Swap Shop Discussion Group
Bob's Rockshop Rock Net Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Ask-A-Mineralogist from the Mineralogical Society of America
|
|
|
|
|