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Holdawayite
A valid IMA mineral species
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About Holdawayite
Formula:
Mn6(CO3)2(OH)7(Cl,OH)
Colour:
Light to bright pink
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
3.19
Crystal System:
Monoclinic
Name:
Named in honor of Michael Jon Holdaway (b. 1936, d. March 21, 2025), professor of petrology and Southern Methodist University, Dallas, Texas, USA, for his contributions to mineralogy ind petrology and for his efforts as editor of the American Mineralogist.
This page provides mineralogical data about Holdawayite.
Unique Identifiers
Mindat ID:
1919
Long-form identifier:
mindat:1:1:1919:0
IMA Classification of Holdawayite
Approved
IMA Formula:
Mn2+6(CO3)2(OH)7(Cl,OH)
Approval year:
1986
First published:
1988
Classification of Holdawayite
5.BA.20
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
A : With Cu, Co, Ni, Zn, Mg, Mn
5 : CARBONATES (NITRATES)
B : Carbonates with additional anions, without H2O
A : With Cu, Co, Ni, Zn, Mg, Mn
16b.4.2.2
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
4 : AmBn(XO3)pZqxH2O & with (m+n):p = 3:1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
4 : AmBn(XO3)pZq
11.12.2
11 : Carbonates
12 : Carbonates of Mn
11 : Carbonates
12 : Carbonates 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 |
|---|---|---|
| Hdw | 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 Holdawayite
Vitreous
Transparency:
Translucent
Colour:
Light to bright pink
Comment:
It gradually changes to a brown color on exposure and in some cases has developed a thin black sooty coating that masks the true color
Streak:
Light pink
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{100}
{100}
Density:
3.19(4) g/cm3 (Measured) 3.24 g/cm3 (Calculated)
Optical Data of Holdawayite
Type:
Biaxial (-)
RI values:
nα = 1.644(1) nβ = 1.719(1) nγ = 1.721(1)
2V:
Measured: 12° to 18°, Calculated: 16°
Max. Birefringence:
δ = 0.077
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:
relatively strong
Optical Extinction:
X = b; Z ∧ c = 45(3)° in the obtuse angle of beta.
Pleochroism:
Non-pleochroic
Chemistry of Holdawayite
Mindat Formula:
Mn6(CO3)2(OH)7(Cl,OH)
Element Weights:
Crystallography of Holdawayite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 23.437(5) Å, b = 3.3137(3) Å, c = 16.618(6) Å
β = 111.15(2)°
β = 111.15(2)°
Ratio:
a:b:c = 7.073 : 1 : 5.015
Unit Cell V:
1,203.67 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Granular aggregates or massive. Fibrous, elongated along [001].
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0001165 | Holdawayite | Peacor D R, Rouse R C (1988) Holdawayite, Mn6(CO3)2(OH)7(Cl,OH), a structure containing anions in zeolite-like channels American Mineralogist 73 637-642 |  | 1988 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.93 Å | (100) |
| 7.77 Å | (40) |
| 5.459 Å | (80) |
| 3.879 Å | (70) |
| 2.926 Å | (40) |
| 2.690 Å | (60b) |
| 2.589 Å | (50b) |
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 Holdawayite
General Appearance of Type Material:
Subhedral crystals approximately 2 cm in diameter.
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, Ontario, Canada, numbers 51510, 51511.
National Museum of Natural History, Washington, D.C., USA, number 163209.
National Museum of Natural History, Washington, D.C., USA, number 163209.
Geological Setting of Type Material:
Tectonically intercalated manganese and iron ores, which are locally dominated by carbonate- and silicate-facies rocks rather than by the more usual hausmannite ores.
Associated Minerals at Type Locality:
Synonyms of Holdawayite
Other Language Names for Holdawayite
Common Associates
Related Minerals - Strunz-mindat Grouping
| 5.BA.05 | Azurite | Cu3(CO3)2(OH)2 |
| 5.BA.10 | Mcguinnessite | (Mg,Cu)2(CO3)(OH)2 |
| 5.BA.10 | Zincrosasite | (Zn,Cu)2(CO3)(OH)2 |
| 5.BA.10 | Parádsasvárite | Zn2(CO3)(OH)2 |
| 5.BA.10 | Rosasite | (Cu,Zn)2(CO3)(OH)2 |
| 5.BA.10 | Nullaginite | Ni2(CO3)(OH)2 |
| 5.BA.10 | Georgeite | [Cu(OH)2-x(H2O)x][CO3]x/2 |
| 5.BA.10 | Glaukosphaerite | (Cu,Ni)2(CO3)(OH)2 |
| 5.BA.10 | Pokrovskite | Mg2(CO3)(OH)2 |
| 5.BA.10 | Kolwezite | CuCo(CO3)(OH)2 |
| 5.BA.10 | Chukanovite | Fe2+2(CO3)(OH)2 |
| 5.BA.10 | Malachite | Cu2(CO3)(OH)2 |
| 5.BA.10 | Perchiazziite | Co2(CO3)(OH)2 |
| 5.BA.15 | Aurichalcite | (Zn,Cu)5(CO3)2(OH)6 |
| 5.BA.15 | Hydrozincite | Zn5(CO3)2(OH)6 |
| 5.BA.25 | 'UM1977-03-COSiO:CaClH' | Ca10-11(CO3)7(SiO4)Cl1-2(OH)1-2 |
| 5.BA.25 | Defernite | Ca6(CO3)1.58(Si2O7)0.21(OH)7[Cl0.50(OH)0.08(H2O)0.42] |
| 5.BA.30 | Sclarite | Zn7(CO3)2(OH)10 |
| 5.BA.30 | Loseyite | (Mn2+,Zn,Mg)4Zn3(CO3)2(OH)10 |
Fluorescence of Holdawayite
None
Other Information
Notes:
Effervesces weakly in dilute HCl. It is stained light pink with an alizain-red-dilute HCl mixture.
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 Holdawayite
mindat.org URL:
https://www.mindat.org/min-1919.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Holdawayite
Reference List:
Peacor, Donald R., Essene, Eric J., Rouse, Roland C., Dunn, Pete J., Nelen, Joseph A., Grice, Joel D., Innes, John, Knorring, Oleg Von (1988) Holdawayite, a new manganese hydroxyl-carbonate from the Kombat mine, Namibia. American Mineralogist, 73 (5-6) 632-636
Peacor, Donald R., Rouse, Roland C. (1988) Holdawayite, Mn6(CO3)2(OH)7(Cl,OH), a structure containing anions in zeolite-like channels. American Mineralogist, 73 (5-6) 637-642
Localities for Holdawayite
Showing 4 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.
Germany | |
| Wittern (2001) |
| Der Aufschluss Vol.55 |
Namibia (TL) | |
| Peacor et al. (1988) |
Romania | |
| Udubasa et al. (1996) +2 other references |
Quick NavTopAbout HoldawayiteUnique IdentifiersIMA 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
Kombat Mine, Kombat, Otavi Constituency, Otjozondjupa Region, Namibia