Ercitite Mineral Data

General Ercitite Information

Chemical Formula:

Na2(H2O)4[Mn+++2(OH)2(PO4)2]

Composition:

Molecular Weight = 225.83 gm

Sodium 9.06 % Na 12.21 % Na₂O

Calcium 0.71 % Ca 0.99 % CaO

Manganese 12.89 % Mn 18.53 % Mn₂O₃

Iron 11.38 % Fe 16.26 % Fe₂O₃

Phosphorus 13.85 % P 31.74 % P₂O₅

Hydrogen 2.23 % H 19.94 % H₂O

Oxygen 49.88 % O

______ ______

100.00 % 99.68 % = TOTAL OXIDE

Empirical Formula:

Na_0.89Ca_0.04Mn³⁺_0.53Fe³⁺_0.46(PO₄)_1.01(OH)•2(H₂O)

Environment:

Strongly oxidizing, low-temperature hydrothermal alteration. Found as an overgrowth on collinsite, fairfieldite, whitlockite, and other phosphates on a fracture surface the cuts an altered nodule of lithophllite.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Tanco pegmatite at Bernic Lake, southeastern Maitoba, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for mineralogist T. Scott Ercit (1957-) of the Canadian Museum of Nature, Ottawa, Canada.

Synonym:

IMA1999-036

Ercitite Image

Images:

Ercitite

Comments: Back-scattered electron images of ercitite (medium gray) showing lath-shaped habit and cleavages and splintering on mechanical disturbance. W: whitlockite, F: fairfieldite, C: unidentified. (CanMin, v 38, p 896).
Location: Tanco pegmatite, southeastern Manitoba, Canada. Scale: Image size 150 µ-m.
© Canadian Mineralogist

Ercitite Crystallography

Axial Ratios:

a:b:c =0.7144:1:2.2811

Cell Dimensions:

a = 6.2499, b = 8.7479, c = 19.9554, Z = 8; V = 1,091.03 Den(Calc)= 2.75

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: C mca

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

By Intensity(I/I_o): 9.9(1)(020), 2.664(0.8)(141), 3.126(0.6)(150,051),3.273(0.6)(141), 4.92(0.5)(011,110), 2.376(0.4)(171), 2.542(0.4)(200,002), 4.102(0.3),

Physical Properties of Ercitite

Cleavage:

{101} Very Good, {010} Very Good

Color:

Dark brown, Black.

Diaphaneity:

Translucent

Fracture:

Brittle - Irregular - Very brittle fracture producing irregular fragments

Habit:

Lath - Shaped like a small, thin plaster lath, tabular (rectangular) in shape.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

3-4 - Calcite-Fluorite

Luster:

Vitreous (Glassy)

Streak:

beige

Optical Properties of Ercitite

Gladstone-Dale:

CI calc= -0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2607,KC= 0.2582
Ncalc = 1.71

Optical Data:

Biaxial (+), a=1.699, b=1.715, g=1.737, bire=0.0380

Calculated Properties of Ercitite

Electron Density:

Bulk Density (Electron Density)=2.73 gm/cc
note: Specific Gravity of Ercitite =2.75 gm/cc.

Fermion Index:

Fermion Index = 0.0026639768
Boson Index = 0.9973360232

Photoelectric:

PE_Ercitite= 7.50 barns/electron
U=PE_Ercitite x rElectron Density= 20.50 barns/cc.

Radioactivity:

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

Ercitite Classification

Dana Class:

42.11.17.02 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.17)Bermanite Group

42.11.17.01 Bermanite MnMn2(PO4)2(OH)2•4(H2O) P 2₁ 2

42.11.17.02 Ercitite! Na2(H2O)4[Mn2(OH)2(PO4)2] C mca 2/m 2/m 2/m

Strunz Class:

08.DJ.35 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DJ -With large and medium-sized cations, (OH, etc.):RO4 = 1:l

08.DJ.35 Ercitite! Na2(H2O)4[Mn2(OH)2(PO4)2] C mca 2/m 2/m 2/m

Other Ercitite Information

References:

NAME( AmMin, vol 86, p767) PHYS. PROP.(AmMin, v86:767; CanMin, v47:173) OPTIC PROP.(AmMin, vol 86, p767)

See Also:

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

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

Ercitite

Na2(H2O)4[Mn+++2(OH)2(PO4)2]
Dana No: 42.11.17.02 Strunz No: 08.DJ.35
Locality:

Notes:

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