Mcnearite Mineral Data
General Mcnearite Information
Chemical Formula:
NaCa5H4(AsO4)5•4(H2O)
Composition:
Molecular Weight = 994.07 gm
Sodium 2.31 % Na 3.12 % Na2 O
Calcium 20.16 % Ca 28.21 % CaO
Arsenic 37.68 % As 57.80 % As2 O5
Hydrogen 1.22 % H 10.87 % H2 O
Oxygen 38.63 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
NaCa5 H4 (AsO4 )5 •4(H2 O)
IMA Status:
Approved IMA 1981
Locality:
Ste.-Marie-aux-Mines, Vosges Mountains, Alsace, France. Link to MinDat.org Location Data.
Name Origin:
Named for Elizabeth McNear, mineralogist and crystallographer, University of Geneva, Switzerland.
Name Pronunciation:
Mcnearite + Pronunciation
Mcnearite Image
Images:
Mcnearite Crystallography
Axial Ratios:
a:b:c =0.9574:1:0.4929
Cell Dimensions:
a = 13.5, b = 14.1, c = 6.95, Z = 2; alpha = 90°, beta = 92°, gamma = 119° V = 1,156.36 Den(Calc)= 2.85
Crystal System:
Triclinic Space Group: P1,P 1
X Ray Diffraction:
By Intensity(I/Io ): 12.33(1), 3.122(0.6), 3.92(0.6),
Physical Properties of Mcnearite
Cleavage:
{???} Perfect
Color:
White.
Density:
2.6
Habit:
Fibrous - Crystals made up of fibers.
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Luster:
Pearly
Streak:
white
Optical Properties of Mcnearite
Gladstone-Dale:
CI meas = -0.109 (Poor) - where the CI = (1-KPDmeas /KC ) CI calc = -0.008 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.1973,KPDmeas = 0.2171,KC = 0.1958 Ncalc = 1.51 - 1.56
Optical Data:
Biaxial (+), a=1.559, b=1.562, g=1.572, bire=0.0130, 2V(Calc)=58, 2V(Meas)=60.
Calculated Properties of Mcnearite
Electron Density:
Bulk Density (Electron Density)=2.76 gm/cc note: Specific Gravity of Mcnearite =2.86 gm/cc.
Fermion Index:
Fermion Index = 0.0004593786 Boson Index = 0.9995406214
Photoelectric:
PEMcnearite = 27.89 barns/electronU=PEMcnearite x r Electron Density= 77.04 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Mcnearite is Not Radioactive
Mcnearite Classification
Dana Class:
39.03.07.01 (39) Hydrated Acid Phosphates, etc
(39.03) with miscellaneous formulae
(39.03.07) Dana Group
39.03.07.01 Mcnearite NaCa5H4(AsO4)5•4(H2O) P1,P 1 Tri
Strunz Class:
08.CJ.55 08 - PHOSPHATES, ARSENATES, VANADATES
08.C - Phosphates without Additional Anions, with H2O
08.CJ -With only large cations
08.CJ.55 Mcnearite NaCa5H4(AsO4)5•4(H2O) P1,P 1 Tri
Other Mcnearite Information
References:
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
See Also:
Links to other databases for Mcnearite :
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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Mcnearite
NaCa5H4(AsO4)5•4(H2O)
Dana No: 39.03.07.01 Strunz No: 08.CJ.55
Locality:
Notes:
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