Irhtemite Mineral Data

General Irhtemite Information

Chemical Formula:

Ca4Mg(AsO3OH)2(AsO4)2•4(H2O)

Composition:

Molecular Weight = 814.37 gm

Calcium 19.69 % Ca 27.54 % CaO

Magnesium 2.98 % Mg 4.95 % MgO

Arsenic 36.80 % As 56.45 % As₂O₅

Hydrogen 1.24 % H 11.06 % H₂O

Oxygen 39.29 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₄Mg(AsO₃OH)₂(AsO₄)₂•4(H₂O)

Environment:

Probably formed from the dehydration of picopharmacolite.

IMA Status:

Approved IMA 1972

Locality:

Irhtem ore deposit, Morocco. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Irhtemite + Pronunciation

Irhtemite Image

Images:

Irhtemite

Comments: Pink acicular divergent microcrystals of irhtemite on matrix.
Location: Irhtem Mine, near Bou-Azzer, Ouarzazate, Morocco. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Irhtemite Crystallography

Axial Ratios:

a:b:c =1.7647:1:1.1434

Cell Dimensions:

a = 16.73, b = 9.48, c = 10.84, Z = 4; beta = 97.25° V = 1,705.48 Den(Calc)= 3.17

Crystal System:

Monoclinic Space Group: Unk

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

By Intensity(I/I_o): 2.963(1), 3.242(1), 2.847(0.9),

Physical Properties of Irhtemite

Color:

Colorless, White, Pale rose, Pink.

Density:

3.09

Diaphaneity:

Transparent to Translucent

Habit:

Spherical - Spherical, rounded aggregates.

Luster:

Silky

Streak:

white

Optical Properties of Irhtemite

Gladstone-Dale:

CI meas= -0.049 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.023 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2013,KPDmeas= 0.2065,KC= 0.1968
Ncalc = 1.61 - 1.62

Optical Data:

Biaxial (+), a=1.634, g=1.642, bire=0.0080

Calculated Properties of Irhtemite

Electron Density:

Bulk Density (Electron Density)=3.07 gm/cc
note: Specific Gravity of Irhtemite =3.17 gm/cc.

Fermion Index:

Fermion Index = 0.0034407267
Boson Index = 0.9965592733

Photoelectric:

PE_Irhtemite= 27.22 barns/electron
U=PE_Irhtemite x rElectron Density= 83.49 barns/cc.

Radioactivity:

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

Irhtemite Classification

Dana Class:

39.02.05.01 (39)Hydrated Acid Phosphates, etc

(39.02)H2 (AB)5 (XO4)4 � x(H2O)

(39.02.05)Dana Group

39.02.05.01 Irhtemite Ca4Mg(AsO3OH)2(AsO4)2•4(H2O) Unk Mono

Strunz Class:

08.CB.55 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CB -With only medium-sized cations, RO4:H2O = 1:1

08.CB.55 Irhtemite Ca4Mg(AsO3OH)2(AsO4)2•4(H2O) Unk Mono

Other Irhtemite Information

References:

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

See Also:

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

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

Irhtemite

Ca4Mg(AsO3OH)2(AsO4)2•4(H2O)
Dana No: 39.02.05.01 Strunz No: 08.CB.55
Locality:

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