Akrochordite Mineral Data
General Akrochordite Information
Chemical Formula:
Mn4Mg(AsO4)2(OH)4•4(H2O)
Composition:
Molecular Weight = 661.99 gm
Magnesium 3.67 % Mg 6.09 % MgO
Manganese 33.20 % Mn 42.86 % MnO
Arsenic 22.64 % As 34.72 % As2 O5
Hydrogen 1.83 % H 16.33 % H2 O
Oxygen 38.67 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Mn2+ 4 Mg(AsO4 )2 (OH)4 •4(H2 O)
Environment:
A rare mineral in hausmannite ore from a metamorphosed Fe-Mn orebody (L�ngban, Sweden); in a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA).
IMA Status:
Valid Species (Pre-IMA) 1922
Locality:
From L�ngban, Varmland, Sweden. At Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA. Link to MinDat.org Location Data.
Name Origin:
From the Greek for wart, for its typical habit.
Name Pronunciation:
Akrochordite + Pronunciation
Synonym:
ICSD 202938
PDF 20-715
Akrochordite Image
Images:
Eveite Akrochordite
Comments: Micro crystals (to about 0.75mm) of very pale grayish green eveite in tiny vug with light pink akrochordite. Co-Type specimen & type locality.
Location: Langban, Varmland, Sweden.
Scale: 13x10x4 mm.
© Tom Loomis / Dakota Matrix
Akrochordite Crystallography
Axial Ratios:
a:b:c =0.3223:1:0.3875
Cell Dimensions:
a = 5.682, b = 17.627, c = 6.832, Z = 2; beta = 99.49° V = 674.91 Den(Calc)= 3.26
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21 /c
X Ray Diffraction:
By Intensity(I/Io ): 4.4(1), 8.79(0.8), 2.75(0.5),
Physical Properties of Akrochordite
Cleavage:
{???} Good
Color:
Reddish brown.
Density:
3.19 - 3.26, Average = 3.22
Diaphaneity:
Translucent
Hardness:
3.5 - Copper Penny
Optical Properties of Akrochordite
Gladstone-Dale:
CI meas = -0.007 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.003 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2077,KPDmeas = 0.2099,KC = 0.2084 Ncalc = 1.66 - 1.68
Optical Data:
Biaxial (?), a=1.672, b=1.676, g=1.683, bire=0.0110
Calculated Properties of Akrochordite
Electron Density:
Bulk Density (Electron Density)=3.13 gm/cc note: Specific Gravity of Akrochordite =3.26 gm/cc.
Fermion Index:
Fermion Index = 0.0038598843 Boson Index = 0.9961401157
Photoelectric:
PEAkrochordite = 23.92 barns/electronU=PEAkrochordite x r Electron Density= 74.92 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Akrochordite is Not Radioactive
Akrochordite Classification
Dana Class:
42.04.01.01 (42) Hydrated Phosphates, etc., Containing Hydroxyl or Halogen
(42.04) where (AB)5 (XO4)2 Zq � x(H2O)
(42.04.01) Akrochordite Group
42.04.01.01 Akrochordite Mn4Mg(AsO4)2(OH)4•4(H2O) P 21 /c 2/m
42.04.01.02 Guanacoite ! (Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2 P 21 /c 2/m
Strunz Class:
08.DD.10 08 - PHOSPHATES, ARSENATES, VANADATES
08.D - Phosphates, etc
08.DD -With only medium-sized cations, (OH, etc.):RO4 = 2:1
08.DD.10 Akrochordite Mn4Mg(AsO4)2(OH)4•4(H2O) P 21 /c 2/m
08.DD.10 Guanacoite ! (Cu,Mg)2Mg2(Mg,Cu)(OH)4(H2O)4(AsO4)2 P 21 /c 2/m
Other Akrochordite Information
References:
NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
See Also:
Links to other databases for Akrochordite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST
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Akrochordite
Mn4Mg(AsO4)2(OH)4•4(H2O)
Dana No: 42.04.01.01 Strunz No: 08.DD.10
Locality:
Notes:
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