Allactite Mineral Data

Allactite Mineral Data +

General Allactite Information

Chemical Formula:

Mn7(AsO4)2(OH)8

Composition:

Molecular Weight = 798.46 gm

Manganese 48.16 % Mn 62.19 % MnO

Arsenic 18.77 % As 28.79 % As₂O₅

Hydrogen 1.01 % H 9.02 % H₂O

Oxygen 32.06 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₇(AsO₄)₂(OH)₈

Environment:

Occurs as a rare secondary mineral in veinlets through metamorphosed manganese deposits )Sweden); in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA).

IMA Status:

Valid Species (Pre-IMA) 1884

Locality:

In Sweden, from the Moss and Brattfors mines, Nordmark, and at Langban, Varmland. From Franklin and Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA. Link to MinDat.org Location Data.

Name Origin:

From the Greek, to change, a reference to the strong pleochroism.

Synonym:

Elfstorpite - Discredited 2004

ICSD 24428

PDF 17-748

Allactite Image

Images:

Allactite

Comments: Brownish red allactite crystals.
Location: Sterling Hill, Ogdensburg, Sussex County, New Jersey, USA. Scale: Size Not Given.
© Lou Perloff / Photo Atlas of Minerals

Allactite Crystallography

Axial Ratios:

a:b:c =0.91:1:0.4546

Cell Dimensions:

a = 11.03, b = 12.12, c = 5.51, Z = 2; beta = 114.083° V = 672.48 Den(Calc)= 3.94

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 3.06(1), 3.71(0.65), 3.28(0.55),

Forms:

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Forms: [ 1 1 1] [ 2 1 0] [ 0 1 0] [ 2 0 1] [ 0 2 1] [ 1 0 0] [ 2 0 1] [ 3 2 1] [ 0 0 1]

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Crystal Structure:

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Moore P B , American Mineralogist , 53 (1968) p.733-741, Crystal chemistry of the basic manganese arsenate minerals: II. The crystal, structure of allactite

Physical Properties of Allactite

Cleavage:

[???] Good

Color:

Brown red, Greenish brown, Purple red, Pink.

Density:

3.83

Diaphaniety:

Translucent

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous - Greasy

Optical Properties of Allactite

Gladstone-Dale:

CI meas= -0.002 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1947,KPDmeas= 0.2003,KC= 0.1998

Optical Data:

Biaxial (-), a=1.755, b=1.772, g=1.774, bire=0.0190, 2V(Calc)=36, 2V(Meas)=0.

Calculated Properties of Allactite

Electron Density:

r_electron=3.62 gm/cc
note: r_Allactite=3.83 gm/cc.

Fermion Index

Fermion Index = 0.00015
Boson Index = 0.99985

Photoelectric:

PE_Allactite= 25.48 barns/electron
U=PE_Allactite x r_electron= 92.14 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Allactite is Not Radioactive

Allactite Classification

Dana Class:

41.2.1.1 (41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen

(41.2)where (A B)7 (XO4)2 Zq

(41.2.1)Dana Group

41.2.1.1 Allactite Mn7(AsO4)2(OH)8 P 2₁/a 2/m

41.2.1.2 Raadeite! Mg7(PO4)2(OH)8 P 2₁/n 2/m

41.2.1.3 IMA2004-035! Mn7(PO4)2(OH)8 P 2₁/c 2/m

Strunz Class:

VII/B.15-50 VII - Phosphates, Arsenates and Vanadates

VII/B - Waterfree phosphates with unfamiliar anions F, Cl, O,OH, cations of medium size: Mg, Mn, Fe, Cu, Zn, Pseudomalachite group and related compounds

VII/B.15 - Pseudomalachite group, Flinkite - Allactite series

VII/B.15-10 Flinkite Mn2Mn(AsO4)(OH)4 P nma 2/m 2/m 2/m

VII/B.15-20 Retzian-(La) (Mn,Mg)2(La,Ce,Nd)(AsO4)(OH)4 Pban 2/m 2/m 2/m

VII/B.15-30 Retzian-(Ce) Mn2Ce(AsO4)(OH)4 Pban 2/m 2/m 2/m

VII/B.15-40 Retzian-(Nd) Mn2(Nd,Ce,La)(AsO4)(OH)4 Pban 2/m 2/m 2/m

VII/B.15-45 Raadeite! Mg7(PO4)2(OH)8 P 2₁/n 2/m

VII/B.15-50 Allactite Mn7(AsO4)2(OH)8 P 2₁/a 2/m

Other Allactite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

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

Allactite

Mn7(AsO4)2(OH)8
Dana No: 41.2.1.1 Strunz No: VII/B.15-50
Locality:

Notes: