Penobsquisite
A valid IMA mineral species
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Penobsquis, New Brunswick, Canada
Formula:
Ca2Fe2+[B9O13(OH)6]Cl · 4H2O
Colour:
Pale yellow
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.26
Crystal System:
Monoclinic
Name:
Named for the town of Penobsquis, New Brunswick, Canada, near the type locality. Pronounced penob'skwisait.
This page provides mineralogical data about Penobsquisite.
Unique Identifiers
Mindat ID:
7223
Long-form identifier:
mindat:1:1:7223:2
IMA Classification of Penobsquisite
Approved
IMA Formula:
Ca2Fe2+[B9O13(OH)6]Cl(H2O)2·2H2O
Approval year:
1995
First published:
1996
Classification of Penobsquisite
6.GB.10
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 |
|---|---|---|
| Pnb | 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 Penobsquisite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Pale yellow
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
2.26(3) g/cm3 (Measured) 2.27 g/cm3 (Calculated)
Optical Data of Penobsquisite
Type:
Biaxial (+/-)
RI values:
nα = 1.550(2) nβ = 1.554(2) nγ = 1.592(2)
2V:
Measured: 33° (2), Calculated: 37°
Max. Birefringence:
δ = 0.042
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:
Moderate
Dispersion:
None.
Optical Extinction:
Y = b; Z ∧ C = 16.6° in obtuse angle beta.
Pleochroism:
Not Visible
Chemistry of Penobsquisite
Mindat Formula:
Ca2Fe2+[B9O13(OH)6]Cl · 4H2O
Element Weights:
Crystallography of Penobsquisite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Setting:
P21
Cell Parameters:
a = 11.620(3) Å, b = 9.407(2) Å, c = 8.726(1) Å
β = 95.58(2)°
β = 95.58(2)°
Ratio:
a:b:c = 1.235 : 1 : 0.928
Unit Cell V:
949.31 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Unusual morphology. Equidimensional to tabular on {100}, often slightly elongate on [010], triangular in shape.
Forms observed include pinacoids {100}, {101} and {l01}, and the sphenoids {111}, {110}, {l10}, {212} and {112}.
Forms observed include pinacoids {100}, {101} and {l01}, and the sphenoids {111}, {110}, {l10}, {212} and {112}.
Twinning:
None observed
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0005500 | Penobsquisite | Grice J D, Gault R A, Van Velthuizen J (1996) Penobsquisite: A new borate mineral with a complex framework structure The Canadian Mineralogist 34 657-665 |  | 1996 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.65 Å | (30) |
| 7.29 Å | (100) |
| 5.32 Å | (20) |
| 4.50 Å | (20) |
| 2.958 Å | (30) |
| 2.744 Å | (20) |
| 2.113 Å | (30) |
Comments:
Potash Corporation of Saskatchewan Mine, New Brunswick, Canada. The data are from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Penobsquisite
General Appearance of Type Material:
Euhedral crystals to 1.5 mm, found as residue obtained from the dissolution of a halite drill-core.
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, catalogue number CMNMI 81524.
Geological Setting of Type Material:
Potash and halite deposit
Associated Minerals at Type Locality:
Synonyms of Penobsquisite
Other Language Names for Penobsquisite
Related Minerals - Strunz-mindat Grouping
| 6.GB.05 | Studenitsite | NaCa2[B9O14(OH)4] · 2H2O |
| 6.GB.15 | Preobrazhenskite | Mg3B11O15(OH)9 |
| 6.GB.20 | Walkerite | Ca16(Mg,Li,◻)2[B13O17(OH)12]4Cl6 · 28H2O |
Fluorescence of Penobsquisite
None observed.
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 Penobsquisite
mindat.org URL:
https://www.mindat.org/min-7223.html
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References for Penobsquisite
Reference List:
Grice, Joel D., Gault, Robert A., Van Velthuizen, Jerry (1996) Penobsquisite: A new borate mineral with a complex framework structure. The Canadian Mineralogist, 34 (3) 657-665
Localities for Penobsquisite
Showing 2 localities.
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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. (1996) |
| Burns et al. (1992) |
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