Jedwabite Mineral Data

General Jedwabite Information

Chemical Formula:

Fe7(Ta,Nb)3

Composition:

Molecular Weight = 708.80 gm

Tantalum 38.29 % Ta

Niobium 6.55 % Nb

Iron 55.15 % Fe

______

100.00 %

Empirical Formula:

Fe⁰⁺₇Ta_1.5Nb_0.5

Environment:

Discovered in platiniferous placers in the Nizhnetagilsky District in the Middle Urals, in a collection made by P. Walther at the beginning of the 20th century, in association with niobocarbide and a tantalum carbide.

IMA Status:

Approved IMA 1995 (Dana # Added)

Locality:

Nijniy-Tagil, near Solovjeva mountains (formerly Aurorinsky mine) and Baranchinsky massif near the Aktai River, Middle Urals, Russia. Link to MinDat.org Location Data.

Name Origin:

For Jacques Jedwab, Universite Libre de Bruxelles, Belgique, in recognition of his meticulous investigations of the mineralogy of placers and of carbides in natural environments.

Name Pronunciation:

Jedwabite + Pronunciation

Synonym:

IMA1995-043

Jedvabite

Jedwabite Crystallography

Axial Ratios:

a:c = 1:1.63617

Cell Dimensions:

a = 4.81, c = 7.87, Z = 1; V = 157.69 Den(Calc)= 7.46

Crystal System:

Hexagonal - Dihexagonal Pyramidal H-M Symbol (6mm) Space Group: P 6₃mmc, P 6₃mc

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

By Intensity(I/I_o): 2.05(1), 1.347(0.8), 2.19(0.7),

Physical Properties of Jedwabite

Cleavage:

None

Color:

Grayish yellow.

Density:

8.6

Diaphaneity:

Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

7 - Quartz

Luster:

Metallic

Optical Properties of Jedwabite

RL Anisotrophism:

Negligible.

RL Bireflectance:

Negligible.

RL Color:

Grayish white.

RL Pleochroism:

None.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Jedwabite in Air**
λ	R	∑ R(λ)
420 nm	50.00
440 nm	52.60
460 nm	55.40
480 nm	55.30
500 nm	57.30
520 nm	59.00
540 nm	60.80
560 nm	60.80
580 nm	62.40
600 nm	60.40
640 nm	62.40
650 nm	62.40
680 nm	62.20
700 nm	63.30

**Calculated Relative Intensity Colors of Jedwabite in Air**
Relative Intensity	0%	20%	40%	60%	80%	100%	120%	140%	160%	170%
R

Calculated Properties of Jedwabite

Electron Density:

Bulk Density (Electron Density)=6.57 gm/cc
note: Specific Gravity of Jedwabite =7.46 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Jedwabite= 476.49 barns/electron
U=PE_Jedwabite x rElectron Density=3,129.34 barns/cc.

Radioactivity:

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

Jedwabite Classification

Dana Class:

01.01.24.01 (01)Native Elements

(01.01)with metallic elements other than the platinum group

(01.01.24)Dana Group

01.01.24.01 Jedwabite! Fe7(Ta,Nb)3 P 6₃mmc, P 6₃mc 6mm

Strunz Class:

01.AE.25 01 - ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)

01.A - Metals and Intermetallic Alloys

01.AE -Iron-chromium family

01.AE.25 Jedwabite! Fe7(Ta,Nb)3 P 6₃mmc, P 6₃mc 6mm

Other Jedwabite Information

References:

NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.83,p654,1998) OPTIC PROP.(AmMin, v 83, p 654)

See Also:

Links to other databases for Jedwabite :
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

Search for Jedwabite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Jedwabite :

Ask about Jedwabite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Jedwabite

Fe7(Ta,Nb)3
Dana No: 01.01.24.01 Strunz No: 01.AE.25
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.