Donwilhelmsite
A valid IMA mineral species
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Don E. Wilhelms
Formula:
CaAl4Si2O11
Crystal System:
Hexagonal
Name:
Named in honor of Don Edward Wilhelms (b. 5 July 1930, Los Angeles, California, U.S.A), geologist with United States Geological Survey (USGS), Flagstaff who contributed significantly to the geologic mapping of the Earth's moon and to the geologic training of the Apollo astronauts. He wrote 'The Geologic History of the Moon' about lunar stratigraphy and 'To a Rocky Moon: A Geologist's History of Lunar Exploration'.
Structurally related to zagamiite. May be the Ca analogue of UM2004-47-SiO:AlCaNa.
The acicular habit and the very small size of these phases reflect rapid growth of the crystals during elevated shock pressures in less than tens of microseconds.
Suggested formation genesis:
- on the Moon: from primordial feldspathic crust, during impact cratering
- in the meteorite: shock metamorphism
- in the Earth's mantle: recycling of aluminous crustal materials
Suggested to be a very important Ca and Al sink in subducted sediments in the transition zone and the uppermost mantle. It is also related to a gap between kyanite and the Ca-component of clinopyroxene (kushiroite?) at low pressures and the Al-rich Ca-ferrite and Ca-perovskite (most likely CaSiO3?) at high pressures.
Expected to decompose into minerals like garnet, kyanite, and clinopyroxene, in ascending plumes within the mantle.
The acicular habit and the very small size of these phases reflect rapid growth of the crystals during elevated shock pressures in less than tens of microseconds.
Suggested formation genesis:
- on the Moon: from primordial feldspathic crust, during impact cratering
- in the meteorite: shock metamorphism
- in the Earth's mantle: recycling of aluminous crustal materials
Suggested to be a very important Ca and Al sink in subducted sediments in the transition zone and the uppermost mantle. It is also related to a gap between kyanite and the Ca-component of clinopyroxene (kushiroite?) at low pressures and the Al-rich Ca-ferrite and Ca-perovskite (most likely CaSiO3?) at high pressures.
Expected to decompose into minerals like garnet, kyanite, and clinopyroxene, in ascending plumes within the mantle.
Unique Identifiers
Mindat ID:
53358
Long-form identifier:
mindat:1:1:53358:6
GUID
(UUID V4):
(UUID V4):
9cf56b1d-123a-42a7-b1cb-d46ce7821548
Classification of Donwilhelmsite
Approved
Approval year:
2019
First published:
2020
9.HA.37
9 : SILICATES (Germanates)
H : Unclassified silicates
A : With Alkali and Alkali-earth Elements
9 : SILICATES (Germanates)
H : Unclassified silicates
A : With Alkali and Alkali-earth Elements
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 |
|---|---|---|
| Dwh | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Chemical Properties of Donwilhelmsite
Formula:
CaAl4Si2O11
Elements listed:
Crystallography of Donwilhelmsite
Crystal System:
Hexagonal
Class (H-M):
6/mmm (6/m 2/m 2/m) - Dihexagonal Dipyramidal
Space Group:
P63/mmc
Setting:
P63/mmc
Cell Parameters:
a = 5.44(1) Å, c = 12.76(3) Å
Ratio:
a:c = 1 : 2.346
Unit Cell V:
327.02 ų (Calculated from Unit Cell)
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| - Å | () |
Comments:
X-ray powder diffraction pattern not available (CNMNC Newsletter No. 47). Structure was determined using three-dimensional electron diffraction (3D ED).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 39 : High-? metamorphism (blueschist, eclogite, ultrahigh ? facies) |
Geological Setting:
Probably occurs in the uppermost lower mantle (460–700 km)
Type Occurrence of Donwilhelmsite
General Appearance of Type Material:
Shock melt pockets 100 µm in size of roughly anorthitic chemical composition contain bundles of up to 20 µm long and less than 1 µm wide needle-shaped crystals.
Place of Conservation of Type Material:
Type material is deposited in the mineralogical collections of the Naturhistorisches Museum Wien, Burgring 7, 1010 Wien, Austria, catalogue no. NHMW-O104.
Geological Setting of Type Material:
Lunar meteorite.
Reference:
Fritz, J., Greshake, A., Klementova, M., Wirth, R., Palatinus, L., Trønnes, R.G., Fernandes, V.A., Böttger, U., Ferrière, L. (2020) Donwilhelmsite, [CaAl4Si2O11], a new lunar high-pressure Ca-Al-silicate with relevance for subducted terrestrial sediments. American Mineralogist: 105(11): 1704–1711. doi: https://doi.org/10.2138/am-2020-7393
Synonyms of Donwilhelmsite
Related Minerals - Strunz-mindat Grouping
| 9.HA. | Qeltite | Ca3TiSi2(Fe3+2Si)O14 |
| 9.HA. | Shinichengite | Ca5[BSi2O7(OH)2]2 · 6H2O |
| 9.HA.05 | Ertixiite | Na2Si4O9 |
| 9.HA.10 | Kenyaite | Na2Si22O41(OH)8 · 6H2O |
| 9.HA.20 | Wawayandaite | Ca6Mn2BBe9Si6O23(OH,Cl)15 |
| 9.HA.25 | Magbasite | KBaFe3+Mg7Si8O22(OH)2F6 |
| 9.HA.35 | Demagistrisite | BaCa2Mn3+4(Si3O10)(Si2O7)(OH)4 · 3H2O |
| 9.HA.40 | Igumnovite | Ca3Al2[SiO4]2[◻Cl4] |
| 9.HA.40 | Kasatkinite | Ba2Ca8B5Si8O32(OH)3 · 6H2O |
| 9.HA.42 | Paqueite | Ca3TiSi2(Al,Ti,Si)3O14 |
| 9.HA.45 | Rippite | K2(Nb,Ti)2(Si4O12)O(O,F) |
| 9.HA.47 | Zagamiite | CaAl2Si3.5O11 |
| 9.HA.50 | α-Carnegieite | NaAlSiO4 |
| 9.HA.50 | Rudenkoite | Sr3(Al3.5Si3.5)O10(OH,O)8Cl2 · H2O |
| 9.HA.52 | Atheriastite | near Ca5MgFeAl6Si8O32 · 5H2O |
| 9.HA.55 | Balvraidite | |
| 9.HA.55 | Foshallasite | Ca3[Si2O7] · 3H2O(?) |
| 9.HA.57 | Bhreckite | Ca, Mg, Fe, Si, O, H |
| 9.HA.60 | Bravaisite | |
| 9.HA.60 | Nagelschmidtite | Ca7(SiO4)2(PO4)2 |
| 9.HA.65 | Caryochroite | (Na,Sr)3(Fe3+,Mg)10[Ti2Si12O37] · (H2O,O,OH)17 |
| 9.HA.70 | Juanite | Ca10Mg4Al2Si11O39 · 4H2O or near |
| 9.HA.75 | Tacharanite | Ca12Al2Si18O33 (OH)36 |
| 9.HA.80 | Oyelite | Ca10Si8B2O29 · 12.5H2O |
| 9.HA.85 | Denisovite | K14+x(Ca,Na,Mn,Fe)48[Si60O162]F16(Ox,OH4-x) · 2H2O |
| 9.HA.90 | Tiettaite | K4Na12Fe3+Si16O41(OH)4 · 2H2O |
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 Donwilhelmsite
mindat.org URL:
https://www.mindat.org/min-53358.html
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External Links:
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References for Donwilhelmsite
Reference List:
Localities for Donwilhelmsite
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 | |
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Morocco (TL) | |
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