Gormanite Mineral Data
General Gormanite Information
Chemical Formula:
Fe++3Al4(PO4)4(OH)6•2(H2O)
Composition:
Molecular Weight = 793.43 gm
Aluminum 13.60 % Al 25.70 % Al2 O3
Iron 21.12 % Fe 27.17 % FeO
Phosphorus 15.62 % P 35.78 % P2 O5
Hydrogen 1.27 % H 11.35 % H2 O
Oxygen 48.40 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Fe2+ 3 Al4 (PO4 )4 (OH)6 •2(H2 O)
Environment:
Phosphate ironstones. Forms a series with souzalite.
IMA Status:
Approved IMA 1981
Locality:
Rapid Creek and Big Fish area, Yukon Territory, Canada. Link to MinDat.org Location Data.
Name Origin:
Named for Donald Herbert Groman (1922-), University of Toronto, Canada.
Name Pronunciation:
Gormanite + Pronunciation
Synonym:
IMA1977-030
Gormanite Image
Images:
Gormanite
Comments: Elongated, dark bluish green, fibrous crystals of gormanite and quartz on a matrix of quartz and water clear apatite crystals.
Location: Big Fish River, Yukon Territory, Canada.
Scale: 4.8 x 3.8 cm.
© John Veevaert
Images:
Gormanite
Comments: Dark green, velvety mass of gormanite crystals on matrix.
Location: Rapid Creek, Yukon Territory, Canada.
Scale: 3 x 4.5 cm.
© Dave Barthelmy
Gormanite Crystallography
Axial Ratios:
a:b:c =2.3072:1:2.6555
Cell Dimensions:
a = 11.79, b = 5.11, c = 13.57, Z = 2; alpha = 90.83°, beta = 99.25°, gamma = 90.082° V = 806.83 Den(Calc)= 3.27
Crystal System:
Triclinic Space Group: P1,P 1
X Ray Diffraction:
By Intensity(I/Io ): 3.395(1), 2.554(0.9), 2.925(0.8),
Physical Properties of Gormanite
Cleavage:
{001} Indistinct
Color:
Blue green.
Density:
3.13
Habit:
Aggregates - Made of numerous individual crystals or clusters.
Habit:
Bladed - Aggregates of thin lath-like crystals (e.g. kyanite).
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
4-5 - Fluorite-Apatite
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Streak:
pale green
Optical Properties of Gormanite
Gladstone-Dale:
CI meas = 0.012 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.055 (Good) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.1969,KPDmeas = 0.2058,KC = 0.2084 Ncalc = 1.65 - 1.68
Optical Data:
Biaxial (-), a=1.619, b=1.653, g=1.66, bire=0.0410, 2V(Calc)=48, 2V(Meas)=53.
Pleochroism (x):
colorless.
Pleochroism (y):
blue.
Pleochroism (z):
colorless.
Calculated Properties of Gormanite
Electron Density:
Bulk Density (Electron Density)=3.09 gm/cc note: Specific Gravity of Gormanite =3.13 gm/cc.
Fermion Index:
Fermion Index = 0.0047108218 Boson Index = 0.9952891782
Photoelectric:
PEGormanite = 7.39 barns/electronU=PEGormanite x r Electron Density= 22.85 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Gormanite is Not Radioactive
Gormanite Classification
Dana Class:
42.09.02.02 (42) Hydrated Phosphates, etc., Containing Hydroxyl or Halogen
(42.09) where (A)3 (XO4)2 Zq � x(H2O)
(42.09.02) Souzalite Group
42.09.02.01 Souzalite (Mg,Fe)3(Al,Fe)4(PO4)4(OH)6•2(H2O) P1,P 1 Tri
42.09.02.02 Gormanite Fe3Al4(PO4)4(OH)6•2(H2O) P1,P 1 Tri
42.09.02.03 Andyrobertsite ! KCdCu5(AsO4)4[As(OH)2O2]•2(H2O) P 21 /m 2/m
42.09.02.04 Calcioandyrobertsite-1M ! KCaCu5(AsO4)4[As(OH)2O2]•2(H2O) P 21 /m 2/m
42.09.02.05 Calcioandyrobertsite-2O ! KCaCu5(AsO4)4[As(OH)2O2]•2(H2O) P nma 2/m 2/m 2/m
Strunz Class:
08.DC.45 08 - PHOSPHATES, ARSENATES, VANADATES
08.D - Phosphates, etc
08.DC -With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1
08.DC.45 Gormanite Fe3Al4(PO4)4(OH)6•2(H2O) P1,P 1 Tri
08.DC.45 Souzalite (Mg,Fe)3(Al,Fe)4(PO4)4(OH)6•2(H2O) P1,P 1 Tri
Other Gormanite Information
References:
NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
See Also:
Links to other databases for Gormanite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
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
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Gormanite
Fe++3Al4(PO4)4(OH)6•2(H2O)
Dana No: 42.09.02.02 Strunz No: 08.DC.45
Locality:
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