Aenigmatite Mineral Data

Aenigmatite Mineral Data +

We specialise in top quality, fine minerals from Morocco, Namibia,
South Africa, Pakistan, Democratic Republic of Congo (ZaÃƒï¿½Ã‚Â¯re) and China
Worldwide Fine Minerals by B & C GOBIN

General Aenigmatite Information

Chemical Formula:

Na2Fe++5TiSi6O20

Composition:

Molecular Weight = 861.60 gm

Sodium 5.34 % Na 7.19 % Na₂O

Titanium 5.56 % Ti 9.27 % TiO₂

Iron 32.41 % Fe 41.69 % FeO

Silicon 19.56 % Si 41.84 % SiO₂

Oxygen 37.14 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₂Fe²⁺₅TiSi₆O₂₀

Environment:

A primary constituent in sodium-rich alkalic volcanics, pegmatites, and other silica-poor igneous rocks.

IMA Status:

Valid Species (Pre-IMA) 1865

Locality:

Notable studied occurrences include: at Naujakasik, near the Tunugdliarfik Fjord, and on the Kangerdluarssuk Plateau, in the Ilimaussaq intrusion; from Narssarssuk; and elsewhere in Gr Link to MinDat.org Location Data.

Name Origin:

From the Greek for riddle, apparently an allusion to its (formerly) uncertain chemical composition.

Synonym:

Cossyrite

ICSD 15283

PDF 46-1473

Aenigmatite Image

Images:

Aenigmatite

Comments: Dark, crystal prism of aenigmatite in white albite with astrophyllite.
Location: Mount Eveslogchorr, Khibiny Massif, Kola Peninsula, Murmansk District, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Aenigmatite Crystallography

Axial Ratios:

a:b:c =0.9623:1:0.8254

Cell Dimensions:

a = 10.406, b = 10.813, c = 8.926, Z = 2; alpha = 104.933°, beta = 96.866°, gamma = 128.316° V = 755.95 Den(Calc)= 3.78

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.14(1), 8.11(1), 2.705(0.8),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Cannillo E , Mazzi F , Fang J H , Robinson P D , Ohya Y , American Mineralogist , 56 (1971) p.427-446, The crystal structure of aenigmatite, sample CM

View Additional jPOWD Structure files for Aenigmatite
[1] [2] [3]

Physical Properties of Aenigmatite

Cleavage:

[???] Perfect

Color:

Brown, Black.

Density:

3.74 - 3.85, Average = 3.79

Diaphaniety:

Opaque

Habit:

Lamellar - Thin laminae producing a lamellar structure.

Hardness:

5-6 - Between Apatite and Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Subadamantine

Streak:

reddish brown

Optical Properties of Aenigmatite

Gladstone-Dale:

CI meas= -0.013 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2191,KPDmeas= 0.2183,KC= 0.2155

Optical Data:

Biaxial (+), a=1.78-1.8, b=1.8-1.82, g=1.87-1.9, bire=0.0900-0.1000, 2V(Calc)=56-60, 2V(Meas)=27-55. Dispersion single.

Pleochroism (x):

light brown.

Pleochroism (y):

brown.

Pleochroism (z):

dark brown.

Calculated Properties of Aenigmatite

Electron Density:

r_electron=3.68 gm/cc
note: r_Aenigmatite=3.80 gm/cc.

Fermion Index

Fermion Index = 0.02336
Boson Index = 0.97664

Photoelectric:

PE_Aenigmatite= 11.46 barns/electron
U=PE_Aenigmatite x r_electron= 42.21 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Aenigmatite is Not Radioactive

Aenigmatite Classification

Dana Class:

69.2.1a.1 (69)Inosilicate Chains with Side Branches or Loops

(69.2)with P>2

(69.2.1a)Aenigmatite and related species (Aenigmatite subgroup)

69.2.1a.1 Aenigmatite Na2Fe5TiSi6O20 P1 1

69.2.1a.2 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

69.2.1a.3 Hogtuvaite (Ca,Na)2(Fe,Fe,Ti,Mg,Mn)6(Si,Be,Al)6O20 P1 1

69.2.1a.4 Krinovite NaMg2CrSi3O10 P1 1

69.2.1a.5 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

69.2.1a.6 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

69.2.1a.7 Welshite Ca2Mg4(Mn,Fe)Sb2O2[Si3Be2O18] P1 1

69.2.1a.8 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

69.2.1a.9 IMA2002-009a! Ca2Fe4FeTiSi4BeAlO20 P1 1

Strunz Class:

VIII/F.14-20 VIII - Silicates

VIII/F - Inosilicates (chain and band) modified double chains

VIII/F.14 - Aenigmatite group

VIII/F.14-10 Krinovite NaMg2CrSi3O10 P1 1

VIII/F.14-20 Aenigmatite Na2Fe5TiSi6O20 P1 1

VIII/F.14-30 Wilkinsonite Na2Fe4Fe2Si6O20 P1 1

VIII/F.14-35 Hogtuvaite (Ca,Na)2(Fe,Fe,Ti,Mg,Mn)6(Si,Be,Al)6O20 P1 1

VIII/F.14-40 Dorrite Ca2Mg2Fe4(Al,Fe)4Si2O20 P1,P 1 Tri

VIII/F.14-50 Rhonite Ca2(Mg,Fe,Fe,Ti)6(Si,Al)6O20 P1 1

VIII/F.14-60 Serendibite Ca2(Mg,Al)6(Si,Al,B)6O20 P1 1

VIII/F.14-70 Welshite Ca2Mg4(Mn,Fe)Sb2O2[Si3Be2O18] P1 1

Other Aenigmatite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Aenigmatite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - MinMax(Deutsch)
11 - MinMax(English)
12 - Mineralienatlas (Deutsch)
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

Search for Aenigmatite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Aenigmatite :

AA Mineral Specimens

B & L Fine Minerals

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

MineralsWeb Fine Minerals

The GeoZone

Wrights Rock Shop

Translate Aenigmatite Mineral Data :

Ask about Aenigmatite 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 Aenigmatite Specimen Label here :

Aenigmatite

Na2Fe++5TiSi6O20
Dana No: 69.2.1a.1 Strunz No: VIII/F.14-20
Locality:

Notes: