Triploidite
A valid IMA mineral species - grandfathered
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About Triploidite
Formula:
Mn2+2(PO4)(OH)
Colour:
Red-brown, light pink, yellow-brown; light pink to light brown in transmitted light
Lustre:
Sub-Adamantine, Sub-Vitreous, Resinous, Greasy
Hardness:
4½ - 5
Specific Gravity:
3.70
Crystal System:
Monoclinic
Member of:
Name:
Named in 1878 by George Jarvis Brush and Edward Salisbury Dana from TRIPLite and the Greek "eidos", like, alluding to its resemblance to triplite in habit and chemical composition.
Isostructural with:
Unique Identifiers
Mindat ID:
4022
Long-form identifier:
mindat:1:1:4022:4
IMA Classification of Triploidite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1878
Classification of Triploidite
8.BB.15
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
B : With only medium-sized cations, (OH, etc.):RO4 about 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
B : With only medium-sized cations, (OH, etc.):RO4 about 1:1
41.6.3.2
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
19.12.13
19 : Phosphates
12 : Phosphates of Mn
19 : Phosphates
12 : Phosphates 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.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Tpd | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Tp | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Triploidite
Sub-Adamantine, Sub-Vitreous, Resinous, Greasy
Transparency:
Transparent, Translucent
Colour:
Red-brown, light pink, yellow-brown; light pink to light brown in transmitted light
Streak:
White, off-white
Hardness:
4½ - 5 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
On {010}, good; on {120}, fair; on {110}, very poor.
On {010}, good; on {120}, fair; on {110}, very poor.
Fracture:
Irregular/Uneven
Density:
3.70 g/cm3 (Measured) 3.80 g/cm3 (Calculated)
Comment:
3.66 - estimated value for pure Mn2+ end-member material.
Optical Data of Triploidite
Type:
Biaxial (+)
RI values:
nα = 1.709 - 1.735 nβ = 1.710 - 1.736 nγ = 1.714 - 1.740
Birefringence:
0.005
Max. Birefringence:
δ = 0.005
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.
No measured or calculated 2V is on file for this mineral, so the value used here (53°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (53°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r > v weak
Pleochroism:
Weak
Comments:
Pleochroism faint in thick grains with absorption Z > X, Y.
Comments:
2V moderate.
Chemistry of Triploidite
Mindat Formula:
Mn2+2(PO4)(OH)
Element Weights:
Elements listed:
Crystallography of Triploidite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P2/b
Cell Parameters:
a = 12.366 Å, b = 13.276 Å, c = 9.943 Å
β = 108.23°
β = 108.23°
Ratio:
a:b:c = 0.931 : 1 : 0.749
Unit Cell V:
1,550.42 ų (Calculated from Unit Cell)
Morphology:
Crystals rarely observed, prismatic [001], with the prism zone striated vertically. Parallel-fibrous to columnar aggregates common; also divergent or randomly oriented; fibrous; granular.
Comment:
P21/a
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) |
|---|---|---|---|---|---|---|---|
| 0010707 | Triploidite | Waldrop L (1970) The crystal structure of triploidite and its relation to the structures of other minerals of the triplite-triploidite group Refinement with all F_o's, this is the better refinement Zeitschrift fur Kristallographie 131 1-20 |  | 1970 | Branchville, Connecticut, USA | 0 | 293 |
| 0010706 | Triploidite | Waldrop L (1970) The crystal structure of triploidite and its relation to the structures of other minerals of the triplite-triploidite group Refinement with reflections for which I > 1.2Imin, this is the poorer refinement Zeitschrift fur Kristallographie 131 1-20 | | 1970 | Branchville, Connecticut, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.41 Å | (50) |
| 3.19 Å | (80) |
| 3.10 Å | (90) |
| 2.94 Å | (100) |
| 2.58 Å | (50) |
| 2.31 Å | (50) |
| 1.80 Å | (60) |
Comments:
Branchville, Connecticut, USA
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 21 : Chemically precipitated carbonate, phosphate, iron formations | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Geological Setting:
Granitic pegmatites.
Type Occurrence of Triploidite
General Appearance of Type Material:
Crystalline aggregates that are distinctly parallel-fibrous to columnar in some cases, and in others divergent. Also randomly fibrous to nearly compact massive. Occasionally individual prismatic crystals.
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
Granitic pegmatite.
Associated Minerals at Type Locality:
Other Language Names for Triploidite
Relationship of Triploidite to other Species
Member of:
Other Members of Triplite Group:
| Triplite | Mn2+2(PO4)F | Mon. 2/m |
| Wolfeite | Fe2+2(PO4)(OH) | Mon. 2/m : P21/b |
| Zwieselite | Fe2+2(PO4)F | Mon. 2/m : P21/b |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 9 photos of Triploidite associated with Quartz | SiO2 |
| 9 photos of Triploidite associated with Rhodochrosite | MnCO3 |
| 7 photos of Triploidite associated with Dickinsonite-(KMnNa) | (KNa)(Mn2+◻)Ca(Na2Na)Mn2+13Al(PO4)11(PO4)(OH)2 |
| 6 photos of Triploidite associated with Seamanite | Mn2+3[B(OH)4](PO4)(OH)2 |
| 6 photos of Triploidite associated with Lithiophilite | LiMn2+PO4 |
| 5 photos of Triploidite associated with Natrophilite | NaMn2+PO4 |
| 5 photos of Triploidite associated with Purpurite | Mn3+(PO4) |
| 5 photos of Triploidite associated with 'Cleavelandite' | Na(AlSi3O8) |
| 3 photos of Triploidite associated with Shigaite | Mn6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2O |
| 1 photo of Triploidite associated with Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O |
Related Minerals - Strunz-mindat Grouping
| 8.BB. | Moabite | NiFe3+(PO4)O |
| 8.BB. | Tilasite | CaMg(AsO4)F |
| 8.BB. | Paulgrothite | Cu9Fe3+O4(PO4)4Cl3 |
| 8.BB. | Karlditmarite | Cu9O4(PO4)2(SO4)2 |
| 8.BB. | Milkovoite | Cu4O(PO4)(AsO4) |
| 8.BB.X | Arsenowagnerite | Mg2(AsO4)F |
| 8.BB.05 | Tavorite | LiFe3+(PO4)(OH) |
| 8.BB.05 | Amblygonite | LiAl(PO4)F |
| 8.BB.05 | Montebrasite | LiAl(PO4)(OH) |
| 8.BB.10 | Zwieselite | Fe2+2(PO4)F |
| 8.BB.10 | Triplite | Mn2+2(PO4)F |
| 8.BB.15 | 'Unnamed (Sb-analogue of Auriacusite)' | Fe3+Cu2+[(Sb,As)O4]O |
| 8.BB.15 | Joosteite | Mn2+(Mn3+,Fe3+)(PO4)O |
| 8.BB.15 | Hydroxylwagnerite | Mg2(PO4)(OH) |
| 8.BB.15 | Wagnerite | Mg2(PO4)F |
| 8.BB.15 | Stanĕkite | (Mn2+,Fe2+,Mg)Fe3+(PO4)O |
| 8.BB.15 | Sarkinite | Mn2+2(AsO4)(OH) |
| 8.BB.15 | Wolfeite | Fe2+2(PO4)(OH) |
| 8.BB.20 | Holtedahlite | Mg2(PO4)(OH) |
| 8.BB.20 | Satterlyite | (Fe2+,Mg,Fe)12(PO4)5(PO3OH)(OH,O)6 |
| 8.BB.25 | Althausite | Mg4(PO4)2(OH,O)(F,◻) |
| 8.BB.30 | Zincolivenite | CuZn(AsO4)(OH) |
| 8.BB.30 | Adamite | Zn2(AsO4)(OH) |
| 8.BB.30 | Libethenite | Cu2(PO4)(OH) |
| 8.BB.30 | Zincolibethenite | CuZn(PO4)(OH) |
| 8.BB.30 | Eveite | Mn2+2(AsO4)(OH) |
| 8.BB.30 | Olivenite | Cu2(AsO4)(OH) |
| 8.BB.30 | Auriacusite | Fe3+Cu2+(AsO4)O |
| 8.BB.35 | Paradamite | Zn2(AsO4)(OH) |
| 8.BB.35 | Tarbuttite | Zn2(PO4)(OH) |
| 8.BB.40 | Barbosalite | Fe2+Fe3+2(PO4)2(OH)2 |
| 8.BB.40 | Scorzalite | Fe2+Al2(PO4)2(OH)2 |
| 8.BB.40 | Lazulite | MgAl2(PO4)2(OH)2 |
| 8.BB.40 | Meizhouite | Fe2+V3+2(PO4)2(OH)2 |
| 8.BB.40 | Hentschelite | CuFe3+2(PO4)2(OH)2 |
| 8.BB.40 | Wilhelmkleinite | ZnFe3+2(AsO4)2(OH)2 |
| 8.BB.45 | Dokuchaevite | Cu8O2(VO4)3Cl3 |
| 8.BB.45 | Trolleite | Al4(PO4)3(OH)3 |
| 8.BB.45 | Yaroshevskite | Cu9O2(VO4)4Cl2 |
| 8.BB.50 | Namibite | Cu(BiO)2(VO4)(OH) |
| 8.BB.50 | Aleutite | [Cu5O2](AsO4)(VO4) · (Cu,K,Pb,Rb,Cs,)Cl |
| 8.BB.52a | Ericlaxmanite | Cu4O(AsO4)2 |
| 8.BB.52b | Kozyrevskite | Cu4O(AsO4)2 |
| 8.BB.55 | Phosphoellenbergerite | (Mg,◻)2Mg12(PO4,PO3OH)6(PO3OH,CO3)2(OH)6 |
| 8.BB.55 | Popovite | Cu5O2(AsO4)2 |
| 8.BB.60 | Urusovite | CuAl(AsO4)O |
| 8.BB.65 | Theoparacelsite | Cu3(As2O7)(OH)2 |
| 8.BB.70 | Turanite | Cu5(VO4)2(OH)4 |
| 8.BB.75 | Stoiberite | Cu5(VO4)2O2 |
| 8.BB.80 | Fingerite | Cu11(VO4)6O2 |
| 8.BB.85 | Averievite | Cu6(VO4)2O2Cl2 |
| 8.BB.90 | Richellite | CaFe3+2(PO4)2(OH,F)2 |
| 8.BB.90 | Lipscombite | Fe2+Fe3+2(PO4)2(OH)2 |
| 8.BB.90 | Zinclipscombite | ZnFe3+2(PO4)2(OH)2 |
Fluorescence of Triploidite
Not fluorescent in UV.
Other Information
Thermal Behaviour:
Heated in a closed tube, gives off water with neutral pH, turns black and becomes magnetic. Fuses quietly. Before the blowpipe, colors the flame green.
Notes:
Soluble in acids.
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 Triploidite
mindat.org URL:
https://www.mindat.org/min-4022.html
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References for Triploidite
Reference List:
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.145
Richmond, Wallace E. (1940) Crystal chemistry of the phosphates, arsenates and vanadates of the type A2XO4(Z). American Mineralogist, 25 (7). 441-479
Localities for Triploidite
Showing 39 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.
Argentina | |
| Colombo et al. (2012) |
| Roda-Robles et al. (2012) |
Australia | |
| Plimer et al. (1979) |
| |
| Sorrell (n.d.) +2 other references |
Brazil | |
| Robinson et al. (1998) |
Canada | |
| Černý et al. (1998) +1 other reference |
| Groat et al. (2003) |
| Grantham (1985) |
China | |
| Rao et al. (2014) |
| Laurs et al. (2006) |
Czech Republic | |
| Povondra et al. (eds.) +1 other reference |
| Weber |
Finland | |
| Haapala (1966) +1 other reference |
Germany | |
| Dill et al. (2008) +1 other reference |
| Dill et al. (2011) |
| Kastning et al. (1996) +2 other references | |
Japan | |
| Matsubara et al. (1980) |
Poland | |
| Pieczka et al. (2015) +1 other reference |
| Pieczka et al. (2015) |
| Pieczka et al. (2018) +1 other reference |
Russia | |
| Gonevchuk et al. (2005) |
| Pavel M. Kartashov (n.d.) |
South Africa | |
| Cairncross et al. (1995) |
Sweden | |
| Mason (1940) |
UK | |
| Embrey (1978) +1 other reference |
USA | |
| London et al. (1982) |
| London et al. (1982) |
| Brush and Dana (1878) +3 other references |
| King et al. (1994) +1 other reference |
| Scott Soucey and Tim Blake specimens |
| Czaja (2025) |
| Anna Wilken collection |
| USGS Prof Paper 353 +1 other reference |
| Harvard Mineralogical Museum no. 125568 +2 other references |
| Hanahan (1985) |
| Smith et al. (2000) |
| W.C. van Laer |
| USGS Prof Paper 297A +1 other reference |
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Iron Monarch Main Pit, Iron Knob, Pastoral Unincorporated Area, South Australia, Australia