Pinakiolite
A valid IMA mineral species - grandfathered
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About Pinakiolite
Formula:
(Mg,Mn2+)2Mn3+(BO3)O2
Colour:
Black; deep reddish brown in transmitted light
Lustre:
Pearly, Metallic
Hardness:
6
Specific Gravity:
3.88
Crystal System:
Monoclinic
Member of:
Name:
From the Greek πινάκιον, a small tablet, and λίθος, stone, in allusion to the thin tabular shape of the crystals.
Dimorph of:
Unique Identifiers
Mindat ID:
3214
Long-form identifier:
mindat:1:1:3214:4
IMA Classification of Pinakiolite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
(Mg,Mn2+)2(Mn3+,Sb5+)O2(BO3)
First published:
1891
Classification of Pinakiolite
6.AB.35
6 : BORATES
A : Monoborates
B : BO3, with additional anions; 1(D) + OH, etc.
6 : BORATES
A : Monoborates
B : BO3, with additional anions; 1(D) + OH, etc.
24.2.4.1
24 : ANHYDROUS BORATES
2 : A2BO2[XO3]
24 : ANHYDROUS BORATES
2 : A2BO2[XO3]
9.7.1
9 : Borates
7 : Borates of Mn
9 : Borates
7 : Borates of Mn
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 |
|---|---|---|
| Pki | 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 Pinakiolite
Pearly, Metallic
Transparency:
Translucent, Opaque
Comment:
brilliant on {010}, to pearly
Colour:
Black; deep reddish brown in transmitted light
Streak:
Brown-gray
Hardness:
6 on Mohs scale
Tenacity:
Very brittle
Cleavage:
Distinct/Good
On {010}.
On {010}.
Density:
3.88 g/cm3 (Measured) 3.94(15) g/cm3 (Calculated)
Optical Data of Pinakiolite
Type:
Biaxial (-)
RI values:
nα = 1.908(5) nβ = 2.05(1) nγ = 2.06(10)
2V:
Measured: 31° to 33°, Calculated: 64°
Max. Birefringence:
δ = 0.152
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
Optical Extinction:
X = b; Y = c; Z = a.
Pleochroism:
Visible
Comments:
X = Deep reddish brown
Y = Nearly opaque
Z = Reddish yellow
Y = Nearly opaque
Z = Reddish yellow
Chemistry of Pinakiolite
Mindat Formula:
(Mg,Mn2+)2Mn3+(BO3)O2
Element Weights:
Elements listed:
Crystallography of Pinakiolite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 5.36 Å, b = 5.98 Å, c = 21.79 Å
β = 120.57°
β = 120.57°
Ratio:
a:b:c = 0.896 : 1 : 3.644
Unit Cell V:
601.35 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Thin rectangular tablets {010}. Short prismatic [001], rare. Crystals often bent or broken.
Twinning:
On {011} common as contact and/or cruciform interpenetrant twins.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0000416 | Pinakiolite | Moore P B, Araki T (1974) Pinakiolite, Mg2MnO2[BO3]; warwickite, Mg(Mg0.5Ti0.5)O[BO3]; wightmanite, Mg5(O)(OH)5[BO3].nH2O: Crystal chemistry of complex 3 Angstrom wallpaper structures American Mineralogist 59 985-1004 |  | 1974 | Langban, Sweden | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.51 Å | (10) |
| 2.70 Å | (9) |
| 5.42 Å | (8) |
| 1.986 Å | (6) |
| 2.165 Å | (4) |
| 1.623 Å | (4) |
| 1.496 Å | (4) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Pinakiolite
General Appearance of Type Material:
Bands in matrix.
Place of Conservation of Type Material:
Swedish Museum of Natural History, Stockholm, Sweden, 531826.
Geological Setting of Type Material:
Bands in granular dolomite.
Associated Minerals at Type Locality:
Synonyms of Pinakiolite
Other Language Names for Pinakiolite
Varieties of Pinakiolite
| Sb-rich pinakiolite | Described by Hansen et al. (1988) and Norrestam & Hansen (1990) as a Sb-bearing pinakiolite, a new structural variety from Långban, Sweden. |
Relationship of Pinakiolite to other Species
Member of:
Other Members of Pinakiolite Group:
| Aluminomagnesiohulsite | (Mg,Fe2+)2(Al,Mg,Sn)(BO3)O2 | Mon. 2/m : P2/m |
| Folvikite | Sb5+Mn3+(Mg,Mn2+)10O8(BO3)4 | Mon. 2 : P2 |
| Hulsite | Fe2+2Fe3+O2(BO3) | Mon. 2/m : P2/m |
| Magnesiohulsite | Mg2Fe3+O2(BO3) | Mon. 2/m : P2/m |
Common Associates
Associations Based on Photo Data:
| 8 photos of Pinakiolite associated with Calcite | CaCO3 |
| 6 photos of Pinakiolite associated with Dolomite | CaMg(CO3)2 |
| 1 photo of Pinakiolite associated with Molybdophyllite | Pb8Mg9[Si10O28(OH)8O2(CO3)3] · H2O |
| 1 photo of Pinakiolite associated with Berzeliite | (NaCa2)Mg2(AsO4)3 |
Related Minerals - Strunz-mindat Grouping
| 6.AB. | Chubarovite | KZn2(BO3)Cl2 |
| 6.AB. | Rhabdoborite-(Mo) | Mg12Mo6+1.33O6(BO3)6F2 |
| 6.AB.05 | Hambergite | Be2(BO3)(OH) |
| 6.AB.10 | Berborite | Be2(BO3)(OH) · H2O |
| 6.AB.15 | Jeremejevite | Al6(BO3)5(F,OH)3 |
| 6.AB.20 | Yuanfuliite | Mg(Fe3+,Al)O(BO3) |
| 6.AB.20 | Warwickite | (Mg,Ti,Fe,Al)2O(BO3) |
| 6.AB.25 | Karlite | (Mg,Al)6.5(BO3)3(OH)4(◻,Cl)0.5 |
| 6.AB.30 | Marinaite | Cu2Fe3+O2(BO3) |
| 6.AB.30 | Savelievaite | Mg2Cr3+O2(BO3) |
| 6.AB.30 | Fredrikssonite | Mg2Mn3+O2(BO3) |
| 6.AB.30 | Vonsenite | Fe2+2Fe3+(BO3)O2 |
| 6.AB.30 | Ludwigite | Mg2Fe3+(BO3)O2 |
| 6.AB.30 | Azoproite | (Mg,Fe2+)2(Fe3+,Ti,Mg)(BO3)O2 |
| 6.AB.30 | Bonaccordite | Ni2Fe3+(BO3)O2 |
| 6.AB.35 | Folvikite | Sb5+Mn3+(Mg,Mn2+)10O8(BO3)4 |
| 6.AB.40 | Takéuchiite | (Mg,Mn2+)2(Mn3+,Fe3+)(BO3)O2 |
| 6.AB.40 | Blatterite | Sb5+3(Mn3+,Fe3+)9(Mn2+,Mg)35(BO3)16O32 |
| 6.AB.40 | Orthopinakiolite | (Mg,Mn2+)2Mn3+(BO3)O2 |
| 6.AB.40 | Chestermanite | Mg2(Fe3+,Mn3+,Al,Sb3+)(BO3)O2 |
| 6.AB.45 | Aluminomagnesiohulsite | (Mg,Fe2+)2(Al,Mg,Sn)(BO3)O2 |
| 6.AB.45 | Hulsite | Fe2+2Fe3+O2(BO3) |
| 6.AB.45 | Magnesiohulsite | Mg2Fe3+O2(BO3) |
| 6.AB.50 | Fluoborite | Mg3(BO3)(F,OH)3 |
| 6.AB.50 | Hydroxylborite | Mg3(BO3)(OH)3 |
| 6.AB.55 | Shabynite | Mg5(BO3)(OH)5(Cl,OH)2 · 4H2O |
| 6.AB.55 | Wightmanite | Mg5(BO3)O(OH)5 · 2H2O |
| 6.AB.60 | Gaudefroyite | Ca4Mn3+2-3(BO3)3(CO3)(O,OH)3 |
| 6.AB.65 | Sakhaite | Ca48Mg16(BO3)32(CO3)16 · 2(H2O,HCl) |
| 6.AB.70 | Harkerite | Ca48Mg16[AlSi4O15(OH)]4(BO3)16(CO3)16 · 2(H2O,HCl) |
| 6.AB.75 | Pertsevite-(F) | Mg2(BO3)(F,OH) |
| 6.AB.75 | Pertsevite-(OH) | Mg2(BO3)(OH) |
| 6.AB.80 | Jacquesdietrichite | Cu2(H2BO3)(OH)3 |
| 6.AB.85 | Rhabdoborite-(V) | Mg12(V5+,Mo6+,W6+)1.5O6{[BO3]6-x[(P,As)O4]xF2-x} (x < 1) |
| 6.AB.85 | Rhabdoborite-(W) | Mg12(W6+,V5+)1.5O6{[BO3]6-x[(P,As)O4]xF2-x} |
| 6.AB.85 | Painite | CaZrAl9(BO3)O15 |
| 6.AB.90 | Mengxianminite | (Ca,Na)2Sn2(Mg,Fe)3Al8[(BO3)(BeO4)O6]2 |
Other Information
Notes:
Soluble in concentrated HCl with the evolution of elemental chlorine.
Health Risks:
Emits poisonous chlorine gas when contacted by concentrated HCl.
Internet Links for Pinakiolite
mindat.org URL:
https://www.mindat.org/min-3214.html
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References for Pinakiolite
Reference List:
Flink, G. (1891) Ueber Pinakiolith und Trimerit, zwei neue Mineralien aus den Mangangruben Schwedens. Zeitschrift für Krystallographie, 18 (1). 361-376 doi:10.1524/zkri.1891.18.1.361(as Pinakiolith)
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.120
Takéuchi, Y., Watanabé, T., Ito, T. (1950) The crystal structures of warwickite, ludwigite and pinakiolite. Acta Crystallographica, 3 (2) 98-107 doi:10.1107/s0365110x50000252
Bertaut, E. F. (1950) Structures des boroferrites. Acta Crystallographica, 3 (6) 473-474 doi:10.1107/s0365110x50001312
Moore, Paul Brian, Araki, and Takaharu (1974) Pinakiolite, Mg2Mn3+O2[BO3]; warwickite, Mg(Mg0.5Ti0.5)O[BO3]; wightmanite, Mg5(O)(OH)5[BO3]·nH2O: Crystal chemistry of complex 3 Å wallpaper structures. American Mineralogist, 59 (9-10) 985-1004
Bovin, J.-O., O'Keeffe, M., O'Keefe, M. A. (1981) Electron microscopy of oxyborates. I. Defect structures in the minerals pinakiolite, ludwigite, orthopinakiolite and takéuchiite. Acta Crystallographica Section A, 37 (1) 28-35 doi:10.1107/s0567739481000065
Dunn, Pete J., Chao, George Y., Fitzpatrick, Joan J., Langley, Richard H., Fleischer, Michael, Zilczer, Janet A. (1986) New Mineral Names. American Mineralogist, 71 (1-2). 227-232
Localities for Pinakiolite
Showing 7 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 | |
| Bishop et al. (1974) |
Egypt | |
| Sallam (2020) |
Romania | |
| minerals-of-the-carpathians.eu (2008) |
Sweden (TL) | |
| [var: Sb-rich pinakiolite] Zeits.Krist.Min. (1890) +3 other references |
| Grensman (2003) | |
| www.johnbetts-fineminerals.com (2022) +1 other reference |
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Långban Mine, Långban Ore District, Filipstad, Värmland County, Sweden