Log In
Walkerite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Walkerite
Thomas Leonard Walker
Formula:
Ca16(Mg,Li,◻)2[B13O17(OH)12]4Cl6 · 28H2O
Colour:
Colourless
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.07
Crystal System:
Orthorhombic
Name:
The name honors Thomas Leonard Walker (31 December 1867, Brampton, Ontario, Canada - 6 August 1942, Toronto, Ontario, Canada), Professor and Head of Mineralogy and Petrography, University of Toronto (1901-1937), for his contributions to mineralogy in general and to the studies of the New Brunswick borate deposits in particular. Before his academic career at University of Toronto, Walker was Assistant Director of the Geological Survey of India (1897-1901) and lecturer of the University of Calcutta. He was also the Director of the Department of Mineralogy, Royal Ontario Museum (1913-1942), and the founder in 1921, of Contributions to Canadian Mineralogy, University of Toronto Studies, the predecessor of The Canadian Mineralogist.
This page provides mineralogical data about Walkerite.
Unique Identifiers
Mindat ID:
29154
Long-form identifier:
mindat:1:1:29154:7
Similar Names
| Walkerde | A synonym of Clay minerals |
| Walkerite (of Dana) | A synonym of Montmorillonite |
IMA Classification of Walkerite
Approved
IMA Formula:
Ca16(Mg,Li)2[B13O17(OH)12]4Cl6·28H2O
Approval year:
2001
First published:
2002
Classification of Walkerite
6.GB.20
6 : BORATES
G : Heptaborates and other megaborates
B : Phyllo-nonborates, etc.
6 : BORATES
G : Heptaborates and other megaborates
B : Phyllo-nonborates, etc.
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 |
|---|---|---|
| Wk | 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 Walkerite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless
Streak:
White
Hardness:
3 on Mohs scale
Hardness Data:
Measured
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Splintery
Density:
2.07 g/cm3 (Measured) 2.05 g/cm3 (Calculated)
Optical Data of Walkerite
Type:
Biaxial (+)
RI values:
nα = 1.516 nβ = 1.532 nγ = 1.554
2V:
Measured: 82° (3), Calculated: 82°
Max. Birefringence:
δ = 0.038
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:
None to Very Low
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:
None
Pleochroism:
Non-pleochroic
Chemistry of Walkerite
Mindat Formula:
Ca16(Mg,Li,◻)2[B13O17(OH)12]4Cl6 · 28H2O
Element Weights:
Crystallography of Walkerite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pba2
Cell Parameters:
a = 15.52(1) Å, b = 22.74(1) Å, c = 8.76(4) Å
Ratio:
a:b:c = 0.682 : 1 : 0.385
Unit Cell V:
3,091.62 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Fibrous to bladed crystals to 2mm and bundles to 7 mm. Elongate on [001] with pinacoids {100} and {010} and pedion {001}.
Twinning:
None observed.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0005800 | Walkerite | Grice J D, Gault R A, Van Velthuizen J, Pratt A (2002) Walkerite, a new borate mineral species in an evaporitic sequence from Sussex, New Brunswick, Canada The Canadian Mineralogist 40 1675-1686 |  | 2002 | Sussex, New Brunswick, Canada | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.80 Å | (100) |
| 7.785 Å | (80) |
| 6.319 Å | (40) |
| 5.649 Å | (30) |
| 3.176 Å | (30) |
| 2.570 Å | (30) |
| 6.805 Å | (20) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Walkerite
General Appearance of Type Material:
Fibrous crystals found as residue from dissolving halite drill cores.
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, CMNMC 83379 and CMNMC
83380.
83380.
Geological Setting of Type Material:
Halite member of an evaorite sequence of rocks, near a potash deposit.
Associated Minerals at Type Locality:
Synonyms of Walkerite
Other Language Names for Walkerite
Common Associates
Related Minerals - Strunz-mindat Grouping
| 6.GB.05 | Studenitsite | NaCa2[B9O14(OH)4] · 2H2O |
| 6.GB.10 | Penobsquisite | Ca2Fe2+[B9O13(OH)6]Cl · 4H2O |
| 6.GB.15 | Preobrazhenskite | Mg3B11O15(OH)9 |
Fluorescence of Walkerite
No fluorescence with either short-wave or long-wave ultraviolet light.
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 Walkerite
mindat.org URL:
https://www.mindat.org/min-29154.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Walkerite
Reference List:
Grice, Joel D., Gault, Robert A., Van Velthuizen, Jerry, Pratt, Allen (2002) Walkerite, a new borate mineral species in an evaporitic sequence from Sussex, New Brunswick, Canada. The Canadian Mineralogist, 40 (6) 1675-1686 doi:10.2113/gscanmin.40.6.1675
Localities for Walkerite
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Canada (TL) | |
| Grice et al. (2002) |
Quick NavTopAbout WalkeriteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Potash Corporation of Saskatchewan Mine, Penobsquis, Cardwell Parish, Kings Co., New Brunswick, Canada