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Garyansellite
A valid IMA mineral species
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About Garyansellite
H. Gary Ansell
Formula:
Mg2Fe3+(PO4)2(OH) · 2H2O
Colour:
clove-brown
Lustre:
Vitreous
Hardness:
4
Specific Gravity:
3.16
Crystal System:
Orthorhombic
Member of:
Name:
Named in 1984 by Bozidar Darko Sturman and Pete J. Dunn in honor of Harold Gary Ansell (1943 - 2024), mineralogist with the Canadian Geological Survey. He was curator of the National Mineral Collection from 1972-1997.
Type Locality:
Isostructural with:
Forms a series with kryzhanovskite. Structurally close to other members of the phosphoferrite–reddingite series (or phosphoferrite group).
Small (<1 mm) nearly colorless, zones, fringes, or patches in olive phosphosiderite.
The structure is layered, with layers comprising chains formed by edge-sharing M(2)O4(OH)(H2O) octahedra; these octahedra form dimers and these share edges with separate M(1)O4(H2O)2 octahedra. The chains are linked to layers through the common vertices of M(2); octahedra and octaahedral layers are connected via the phosphate tetrahedra.
Small (<1 mm) nearly colorless, zones, fringes, or patches in olive phosphosiderite.
The structure is layered, with layers comprising chains formed by edge-sharing M(2)O4(OH)(H2O) octahedra; these octahedra form dimers and these share edges with separate M(1)O4(H2O)2 octahedra. The chains are linked to layers through the common vertices of M(2); octahedra and octaahedral layers are connected via the phosphate tetrahedra.
Unique Identifiers
Mindat ID:
1655
Long-form identifier:
mindat:1:1:1655:7
IMA Classification of Garyansellite
Classification of Garyansellite
8.CC.05
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
C : With only medium-sized cations, RO4:H2O = 1:1.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
C : With only medium-sized cations, RO4:H2O = 1:1.5
40.3.2.5
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
3 : A3(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
3 : A3(XO4)2·xH2O
19.14.12
19 : Phosphates
14 : Phosphates of Fe and other metals
19 : Phosphates
14 : Phosphates of Fe and other metals
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Gas | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Garyansellite
Vitreous
Transparency:
Transparent
Comment:
"bronze on cleavages"
Colour:
Clove-brown
Comment:
semitransparent
Streak:
Brown
Hardness:
4 on Mohs scale
Cleavage:
Distinct/Good
{001}
{001}
Density:
3.16(4) g/cm3 (Measured) 3.154 g/cm3 (Calculated)
Optical Data of Garyansellite
Type:
Biaxial (-)
RI values:
nα = 1.733 nβ = 1.757 nγ = 1.761
2V:
Measured: 55° , Calculated: 42°
Max. Birefringence:
δ = 0.028
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r < v
Comments:
reddish brown (X=Z), yellow (Y)
Comments:
Orientation: X = b, Y = a, Z = c; absorption: Z = X > Y
Chemistry of Garyansellite
Mindat Formula:
Mg2Fe3+(PO4)2(OH) · 2H2O
Element Weights:
Common Impurities:
Mn
Crystallography of Garyansellite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 9.45 Å, b = 9.89 Å, c = 8.19 Å
Ratio:
a:b:c = 0.956 : 1 : 0.828
Unit Cell V:
765.44 ų (Calculated from Unit Cell)
Comment:
Space group is Pbna; parameters from Zubkova et al. (2016): a=9.44738, b=9.85976, c=8.14154, V=758.38
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.156 Å | (100) |
| 2.705 Å | (60) |
| 4.93 Å | (50) |
| 3.098 Å | (40) |
| 4.26 Å | (30) |
| 2.535 Å | (30) |
| 2.213 Å | (30) |
Comments:
Rapid Creek, Yukon, Canada. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Garyansellite
General Appearance of Type Material:
Small colorless patches
Place of Conservation of Type Material:
Royal Ontario Museum, Toronto, Canada (registration no. M37306)
Geological Setting of Type Material:
fractures in a sedimentary iron formation; rare, low-temperature species
Associated Minerals at Type Locality:
Synonyms of Garyansellite
Other Language Names for Garyansellite
Relationship of Garyansellite to other Species
Member of:
Other Members of Reddingite Group:
| Correianevesite | Fe2+Mn2+2(PO4)2 · 3H2O | Orth. mmm(2/m2/m2/m) |
| Kryzhanovskite | (Fe3+,Mn2+)3(PO4)2(OH,H2O)3 | Orth. mmm(2/m2/m2/m) |
| Landesite | Mn2+3-xFe3+x(PO4)2(OH)x · (3-x)H2O | Orth. mmm(2/m2/m2/m) |
| Phosphoferrite | (Fe2+,Mn2+)3(PO4)2 · 3H2O | Orth. mmm(2/m2/m2/m) : Pmna |
| Reddingite | (Mn2+,Fe2+)3(PO4)2 · 3H2O | Orth. mmm(2/m2/m2/m) : Pmna |
Forms a series with:
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.CC. | Correianevesite | Fe2+Mn2+2(PO4)2 · 3H2O |
| 8.CC.05 | Landesite | Mn2+3-xFe3+x(PO4)2(OH)x · (3-x)H2O |
| 8.CC.05 | Reddingite | (Mn2+,Fe2+)3(PO4)2 · 3H2O |
| 8.CC.05 | Phosphoferrite | (Fe2+,Mn2+)3(PO4)2 · 3H2O |
| 8.CC.05 | Kryzhanovskite | (Fe3+,Mn2+)3(PO4)2(OH,H2O)3 |
| 8.CC.10 | Kaatialaite | Fe3+[AsO2(OH)2]3 · 5H2O |
| 8.CC.15 | Leogangite | Cu10(AsO4)4(SO4)(OH)6 · 8H2O |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Garyansellite
mindat.org URL:
https://www.mindat.org/min-1655.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
Rapid Creek, Dawson mining district, Yukon, Canada