Monsmedite Mineral Data

General Monsmedite Information

Chemical Formula:

H8K2Tl2(SO4)8•11(H2O)

Composition:

Molecular Weight = 1,461.70 gm

Potassium 5.35 % K 6.44 % K₂O

Thallium 27.97 % Tl 31.25 % Tl₂O₃

Hydrogen 2.07 % H 18.49 % H₂O

Sulfur 17.55 % S 43.82 % SO₃

Oxygen 47.07 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

H₈K₂Tl₂(SO₄)₈•11(H₂O)

Environment:

In the oxidation zone of a silver-bearing lead-zinc deposit. Discredited monsmedite=votaite.

IMA Status:

Discredited IMA 2002

Locality:

Baia Sprie, Baia Mare region, Romania. Link to MinDat.org Location Data.

Name Origin:

Named in 1968 from the Latin 'Mons Medius', for Baia Sprie, Romania, the locality for the mineral.

Name Pronunciation:

Monsmedite + Pronunciation

Synonym:

Discredited

IMA1998-D

Monsmedite Crystallography

Cell Dimensions:

a = 25.29, Z = 20; V = 16,175.08 Den(Calc)= 3.00

Crystal System:

Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3c

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

By Intensity(I/I_o): 3.4(1), 1.57(0.4), 2.08(0.4),2.32(0.4), 3.56(0.4), 2.86(0.4), 3.06(0.1), 5.49(0.1),

Physical Properties of Monsmedite

Cleavage:

{???} Good, {???} Good

Color:

Dark green, Black.

Density:

Diaphaneity:

Subopaque

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Hardness:

2 - Gypsum

Luster:

Resinous

Streak:

dark green

Optical Properties of Monsmedite

Gladstone-Dale:

CI meas= -0.19 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.19 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2018,KPDmeas= 0.2018,KC= 0.1696
Ncalc = 1.51

Optical Data:

Biaxial (-), a=1.6, g=1.611, bire=0.0110

Calculated Properties of Monsmedite

Electron Density:

Bulk Density (Electron Density)=2.88 gm/cc
note: Specific Gravity of Monsmedite =3.00 gm/cc.

Fermion Index:

Fermion Index = 0.0015516873
Boson Index = 0.9984483127

Photoelectric:

PE_Monsmedite= 429.96 barns/electron
U=PE_Monsmedite x r_electron=1,238.97 barns/cc.

Radioactivity:

GRapi = 74.14 (Gamma Ray American Petroleum Institute Units)
Concentration of Monsmedite per GRapi unit = 1.35 (%)

Estimated Radioactivity from Monsmedite - barely detectable

Monsmedite Classification

Dana Class:

29.01.03.01 (29)Hydrated Acid and Sulfates

(29.01)(Hydrated, Acid)

(29.01.03)Dana Group

29.01.03.01 Monsmedite? H8K2Tl2(SO4)8•11(H2O) F d3c 4/m 3 2/m

Strunz Class:

07.CC.25 07 - SULFATES (SELENATES, TELLURATES)

07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O

07.CC -With medium-sized and large cations

07.CC.25 Monsmedite? H8K2Tl2(SO4)8•11(H2O) F d3c 4/m 3 2/m

07.CC.25 Voltaite K2Fe5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m

07.CC.25 Zincovoltaite K2Zn5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m

07.CC.25 Pertlikite! K2(Fe,Mg)2(Mg,Fe)4Fe2Al(SO4)12•18H2O I 4₁/acd 4/m 2/m 2/m

Other Monsmedite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Monsmedite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Ecole des Mines de Paris
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

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

Monsmedite

H8K2Tl2(SO4)8•11(H2O)
Dana No: 29.01.03.01 Strunz No: 07.CC.25
Locality:

Notes:

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