Melanotekite Mineral Data

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General Melanotekite Information

Chemical Formula:

Pb2Fe+++2Si2O9

Composition:

Molecular Weight = 726.26 gm

Iron 15.38 % Fe 21.99 % Fe₂O₃

Silicon 7.73 % Si 16.55 % SiO₂

Lead 57.06 % Pb 61.47 % PbO

Oxygen 19.83 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₂Fe³⁺₂Si₂O₉

Environment:

Occurs with native lead.

IMA Status:

Valid Species (Pre-IMA) 1880

Locality:

Langbanshyttan, Vermland, sweden. Link to MinDat.org Location Data.

Name Origin:

From the Greek black and to melt or glass, for the black bead formed under the blowpipe.

Name Pronunciation:

Melanotekite + Pronunciation

Melanotekite Image

Images:

Melanotekite

Comments: Black metallic granular melanotekite with reddish brown andradite.
Location: Langban, Varmland, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Melanotekite Crystallography

Axial Ratios:

a:b:c =0.6336:1:0.8936

Cell Dimensions:

a = 6.97, b = 11, c = 9.83, Z = 4; V = 753.67 Den(Calc)= 6.40

Crystal System:

Orthorhombic - DisphenoidalH-M Symbol (2 2 2) Space Group: C 222₁

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

By Intensity(I/I_o): 2.732(1), 2.914(1), 5.523(0.8),

Crystal Structure:

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Dorsam G , Liebscher A , Wunder B , Franz G , American Mineralogist , 93 (2008) p.573-583, Crystal structures of synthetic melanotekite (Pb2Fe2Si2O9), kentrolite, (Pb2Mn2Si2O9), and the aluminum analogue (Pb2Al2Si2O9), Locality: synthetic

Physical Properties of Melanotekite

Cleavage:

{???} Good

Color:

Black, Blackish gray.

Density:

5.73

Diaphaneity:

Subtranslucent to opaque

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

6.5 - Pyrite

Luminescence:

Non-fluorescent.

Luster:

Sub Metallic

Streak:

greenish

Optical Properties of Melanotekite

Gladstone-Dale:

CI meas= -0.129 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.011 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1875,KPDmeas= 0.2094,KC= 0.1854
Ncalc = 2.06 - 2.19

Optical Data:

Biaxial (+), a=2.12, b=2.17, g=2.31, bire=0.1900

Calculated Properties of Melanotekite

Electron Density:

Bulk Density (Electron Density)=5.57 gm/cc
note: Specific Gravity of Melanotekite =6.40 gm/cc.

Fermion Index:

Fermion Index = 0.13
Boson Index = 0.87

Photoelectric:

PE_Melanotekite=1,012.03 barns/electron
U=PE_Melanotekite x rElectron Density=5,636.38 barns/cc.

Radioactivity:

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

Melanotekite Classification

Dana Class:

56.02.10.01 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O

(56.02)with cations in [4] and/or >[4] coordination

(56.02.10)Melanotekite group

56.02.10.01 Melanotekite Pb2Fe2Si2O9 C 222₁ 2 2 2

56.02.10.02 Kentrolite Pb2Mn2Si2O9 P bcn 2/m 2/m 2/m

Strunz Class:

09.BE.80 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.80 Kentrolite Pb2Mn2Si2O9 P bcn 2/m 2/m 2/m

09.BE.80 Melanotekite Pb2Fe2Si2O9 C 222₁ 2 2 2

Other Melanotekite Information

References:

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

See Also:

Links to other databases for Melanotekite :
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

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

Melanotekite

Pb2Fe+++2Si2O9
Dana No: 56.02.10.01 Strunz No: 09.BE.80
Locality:

Notes: