Edgarite Mineral Data

General Edgarite Information

Chemical Formula:

FeNb2S6

Composition:

Molecular Weight = 434.06 gm

Niobium 42.81 % Nb

Iron 12.87 % Fe

Sulfur 44.33 % S

______

100.00 %

Empirical Formula:

Fe²⁺Nb₂S₆

Environment:

Coexists with Ti-enriched pyrrhotite in a fenitized xenolith in nepheline syenite.

IMA Status:

Approved IMA 1995 (Dana # Added)

Locality:

Kola Peninsula, northwestern Russia. Link to MinDat.org Location Data.

Name Origin:

Named after Alan D. Edgar (1935-1998), Professor of Petrology, University of Western Ontario, London, Ontario, Canada, in recognition of his contributions to the study of alkaline r ocks and synthetic equivalents.

Synonym:

ICSD 53507

IMA1995-017

PDF 22-350

Edgarite Image

Images:

Edgarite

Comments: Scanning electron micro-image edgarite (EDG, fibrous appearing) inclusion in pyrrhotite (PY) with marcasite (MRC, slightly lower reflectance) in silicate matrix (SIL, lowest reflectance).
Location: Khibiny Massif, Kola Peninsula, Murmansk District, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Edgarite

Comments: Silvery metallic edgarite crystal to about 0.3mm embedded between pegmatite grains.
Location: Khibiny Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia. Scale: Picture size 2 mm.
© Tom Loomis / Dakota Matrix

Edgarite Crystallography

Axial Ratios:

a:c = 1:2.11228

Cell Dimensions:

a = 5.771, c = 12.19, Z = 2; V = 351.59 Den(Calc)= 4.10

Crystal System:

Hexagonal - Trapezohedral H-M Symbol (6 2 2) Space Group: P 6₃22

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.096(1)(114), 1.665(0.8)(300), 6.11(0.8)(002),2.606(0.8)(112), 1.126(0.7)(322), 1.027(0.6)(414), 1.524(0.6)(008), 3.04(0.6)(004),

Physical Properties of Edgarite

Cleavage:

{0001} Perfect

Color:

Dark gray, Black.

Diaphaneity:

Opaque

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

2-2.5 - Gypsum-Finger Nail

Luster:

Metallic

Optical Properties of Edgarite

RL Anisotrophism:

Strong, from almost white to dark brown.

RL Bireflectance:

Distinct.

RL Color:

Similar to molybdenite.

RL Pleochroism:

Distinct, from gray to light gray with a bluish tint.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Edgarite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	28.10	40.20
546 nm	27.40	39.30
589 nm	27.00	38.50
650 nm	27.00	36.90

**Calculated Relative Intensity Colors of Edgarite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	330%
R₁
R₂

Calculated Properties of Edgarite

Electron Density:

Bulk Density (Electron Density)=3.85 gm/cc
note: Specific Gravity of Edgarite =4.10 gm/cc.

Fermion Index:

Fermion Index = 0.0060520482
Boson Index = 0.9939479518

Photoelectric:

PE_Edgarite= 70.79 barns/electron
U=PE_Edgarite x rElectron Density= 272.81 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Edgarite is Not Radioactive

Edgarite Classification

Dana Class:

02.11.13.01 (02)Sulfides - Including Selenides and Tellurides

(02.11)where Am Bn Xp, with (m+n):p=2:3

(02.11.13)Dana Group

02.11.13.01 Edgarite! FeNb2S6 P 6₃22 6 2 2

Strunz Class:

02.DB.25 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.D - Metal Sulfides, M:S = 3:4 and 2:3

02.DB -M:S = 2:3 and similar

02.DB.25 Edgarite! FeNb2S6 P 6₃22 6 2 2

Other Edgarite Information

References:

NAME( CanMin, 8/99) PHYS. PROP.(AmMin, Vol 85, p. 1843) OPTIC PROP.(AmMin, Vol 85, p. 1843)

See Also:

Links to other databases for Edgarite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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Print or Cut-and-Paste your Edgarite Specimen Label here :

Edgarite

FeNb2S6
Dana No: 02.11.13.01 Strunz No: 02.DB.25
Locality:

Notes:

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