Keplerite
A valid IMA mineral species
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About Keplerite
Johannes Kepler
Formula:
Ca9(Ca0.5◻0.5)Mg(PO4)7
Colour:
Colorless
Lustre:
Vitreous
Specific Gravity:
3.122 (Calculated)
Crystal System:
Trigonal
Member of:
Name:
Named in honor of Johannes Kepler (27 December 1571, Free Imperial City of Weil der Stadt, Holy Roman Empire – 15 November 1630, Free Imperial City of Regensburg, Holy Roman Empire), a prominent German naturalist, for his contributions to astronomy and crystallography. He built new refracting telescopes and is best known for his laws of planetary motion, describing the orbits as ellipses for the first time.
The Mg analogue of matyhite. Also the Ca◻- (or Ca0.5◻0.5)-analogue of merrillite.
Related to merrillite via the heterovalent substitution at the B-site: 2Na+ (merrillite) → Ca2+ + □ (keplerite).
A characteristic crystallochemical feature: half-vacant occupancy of the sixfold-coordinated B-site.
Related to merrillite via the heterovalent substitution at the B-site: 2Na+ (merrillite) → Ca2+ + □ (keplerite).
A characteristic crystallochemical feature: half-vacant occupancy of the sixfold-coordinated B-site.
Unique Identifiers
Mindat ID:
54347
Long-form identifier:
mindat:1:1:54347:7
Similar Names
| Kellerite | A variety of Pentahydrite | (Mg,Cu)SO4 · 5H2O |
IMA Classification of Keplerite
Approved
IMA Formula:
Ca9(Ca0.5◻0.5)Mg(PO4)7
Approval year:
2020
First published:
2021
Type description reference:
Britvin, Sergey N., Galuskina, Irina O., Vlasenko, Natalia S., Vereshchagin, Oleg S., Bocharov, Vladimir N., Krzhizhanovskaya, Maria G., Shilovskikh, Vladimir V., Galuskin, Evgeny V., Vapnik, Yevgeny, Obolonskaya, Edita V. (2021) Keplerite, Ca9(Ca0.5☐0.5)Mg(PO4)7, a new meteoritic and terrestrial phosphate isomorphous with merrillite, Ca9NaMg(PO4)7. American Mineralogist, 106 (12) 1917-1927 doi:10.2138/am-2021-7834
Classification of Keplerite
8.AD.
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
D : With only large cations
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
D : With only large cations
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 |
|---|---|---|
| Kep | 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 Keplerite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Cleavage:
None Observed
Density:
3.122 g/cm3 (Calculated)
Optical Data of Keplerite
Type:
Uniaxial (-)
RI values:
nω = 1.622(1) nε = 1.619(1)
Max. Birefringence:
δ = 0.003
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:
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic
Chemistry of Keplerite
Mindat Formula:
Ca9(Ca0.5◻0.5)Mg(PO4)7
Element Weights:
Elements listed:
Crystallography of Keplerite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3c
Cell Parameters:
a = 10.3330(4) Å, c = 37.0668(24) Å
Ratio:
a:c = 1 : 3.587
Unit Cell V:
3427.4 ų
Z:
6
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.166 Å | (25) |
| 3.424 Å | (24) |
| 3.177 Å | (46) |
| 2.854 Å | (100) |
| 2.583 Å | (64) |
| 1.915 Å | (22) |
| 1.877 Å | (19) |
| 1.712 Å | (28) |
Reference:
Britvin, Sergey N., Galuskina, Irina O., Vlasenko, Natalia S., Vereshchagin, Oleg S., Bocharov, Vladimir N., Krzhizhanovskaya, Maria G., Shilovskikh, Vladimir V., Galuskin, Evgeny V., Vapnik, Yevgeny, Obolonskaya, Edita V. (2021) Keplerite, Ca9(Ca0.5☐0.5)Mg(PO4)7, a new meteoritic and terrestrial phosphate isomorphous with merrillite, Ca9NaMg(PO4)7. American Mineralogist, 106 (12) 1917-1927 doi:10.2138/am-2021-7834
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 |
Type Occurrence of Keplerite
Co-Type Localities:
General Appearance of Type Material:
From Marjalahti meteorite: ovoidal to cloudy shape, to 50 μm in size.
Place of Conservation of Type Material:
collections of the Mining Museum, Saint Petersburg Mining University, St. Petersburg, Russia, catalogue number MM74/2-1
Geological Setting of Type Material:
High-temperature environments characterized by extreme depletion of Na; near-end-member mineral: main-group pallasites and angrites; terrestrial material: pyrometamorphic
Associated Minerals at Type Locality:
Reference:
Britvin, Sergey N., Galuskina, Irina O., Vlasenko, Natalia S., Vereshchagin, Oleg S., Bocharov, Vladimir N., Krzhizhanovskaya, Maria G., Shilovskikh, Vladimir V., Galuskin, Evgeny V., Vapnik, Yevgeny, Obolonskaya, Edita V. (2021) Keplerite, Ca9(Ca0.5☐0.5)Mg(PO4)7, a new meteoritic and terrestrial phosphate isomorphous with merrillite, Ca9NaMg(PO4)7. American Mineralogist, 106 (12) 1917-1927 doi:10.2138/am-2021-7834
Other Language Names for Keplerite
Relationship of Keplerite to other Species
Member of:
Other Members of Merrillite Subgroup:
| Ferromerrillite | Ca9NaFe2+(PO4)7 | Trig. 3m : R3c |
| Matyhite | Ca18(Ca,◻)2Fe2+2(PO4)14 | Trig. 3m : R3c |
| Merrillite | Ca9NaMg(PO4)7 | Trig. 3m : R3m |
Common Associates
Associations Based on Photo Data:
| 1 photo of Keplerite associated with Merrillite | Ca9NaMg(PO4)7 |
| 1 photo of Keplerite associated with Fluorapatite | Ca5(PO4)3F |
| 1 photo of Keplerite associated with Diopside | CaMgSi2O6 |
| 1 photo of Keplerite associated with Wollastonite | Ca3(Si3O9) |
Related Minerals - Strunz-mindat Grouping
| 8.AD. | 'Unnamed (Monoclinic polymorph of ximengite)' | Bi(PO4) |
| 8.AD. | Mazorite | Ba3(PO4)2 |
| 8.AD. | Deynekoite | Ca9◻Fe3+(PO4)7 |
| 8.AD. | Monazite-(Gd) | Gd(PO4) |
| 8.AD.05 | Nahpoite | Na2(PO3OH) |
| 8.AD.10 | Weilite | Ca(HAsO4) |
| 8.AD.10 | Švenekite | Ca(H2AsO4)2 |
| 8.AD.10 | Monetite | Ca(PO3OH) |
| 8.AD.15 | Archerite | (K,NH4)(H2PO4) |
| 8.AD.15 | Biphosphammite | NH4(H2PO4) |
| 8.AD.20 | Phosphammite | (NH4)2(PO3OH) |
| 8.AD.25 | Buchwaldite | NaCa(PO4) |
| 8.AD.30 | Schulténite | Pb(HAsO4) |
| 8.AD.35 | Dreyerite | Bi(VO4) |
| 8.AD.35 | Wakefieldite-(La) | La(VO4) |
| 8.AD.35 | Anningite-(Ce) | (Ca0.5Ce4+0.5)(VO4) |
| 8.AD.35 | Pretulite | Sc(PO4) |
| 8.AD.35 | Wakefieldite-(Ce) | Ce(VO4) |
| 8.AD.35 | Wakefieldite-(Y) | Y(VO4) |
| 8.AD.35 | Xenotime-(Yb) | Yb(PO4) |
| 8.AD.35 | 'Chernovite-(Ce)' | (Ce,Y)(AsO4) |
| 8.AD.35 | Xenotime-(Gd) | Gd(PO4) |
| 8.AD.35 | Chernovite-(Y) | Y(AsO4) |
| 8.AD.35 | Xenotime-(Y) | Y(PO4) |
| 8.AD.35 | Wakefieldite-(Nd) | Nd(VO4) |
| 8.AD.40 | Pucherite | Bi(VO4) |
| 8.AD.45 | Ximengite | Bi(PO4) |
| 8.AD.50 | 'UM2005-35-VO:CaFePSiTh' | (Th,Ca)(VO4,SiO4,PO4) |
| 8.AD.50 | Rooseveltite | Bi(AsO4) |
| 8.AD.50 | Gasparite-(Ce) | Ce(AsO4) |
| 8.AD.50 | Monazite-(Sm) | Sm(PO4) |
| 8.AD.50 | Monazite-(Ce) | Ce(PO4) |
| 8.AD.50 | Monazite-(La) | La(PO4) |
| 8.AD.50 | Monazite-(Nd) | Nd(PO4) |
| 8.AD.50 | Gasparite-(La) | La(AsO4) |
| 8.AD.50 | Cheralite | CaTh(PO4)2 |
| 8.AD.55 | Tetrarooseveltite | Bi(AsO4) |
| 8.AD.60 | Chursinite | [Hg2]2+Hg2+2[AsO4]2 |
| 8.AD.65 | Clinobisvanite | Bi(VO4) |
| 8.AD.70 | Gurimite | Ba3(VO4)2 |
| 8.AD.75 | Picaite | NaCa[AsO3OH][AsO2(OH)2] |
Fluorescence of Keplerite
Not fluorescent
Other Information
Notes:
Cation disorder related with vacancy induces splitting of the ν(PO4) vibrational mode (in Raman spectra).
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 Keplerite
mindat.org URL:
https://www.mindat.org/min-54347.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Keplerite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2020) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) - Newsletter 54. European Journal of Mineralogy, 32 (2) 275-283 doi:10.5194/ejm-32-275-2020
Britvin, Sergey N., Galuskina, Irina O., Vlasenko, Natalia S., Vereshchagin, Oleg S., Bocharov, Vladimir N., Krzhizhanovskaya, Maria G., Shilovskikh, Vladimir V., Galuskin, Evgeny V., Vapnik, Yevgeny, Obolonskaya, Edita V. (2021) Keplerite, Ca9(Ca0.5☐0.5)Mg(PO4)7, a new meteoritic and terrestrial phosphate isomorphous with merrillite, Ca9NaMg(PO4)7. American Mineralogist, 106 (12) 1917-1927 doi:10.2138/am-2021-7834
Localities for Keplerite
Showing 5 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.
Brazil | |
| Britvin et al. (2021) |
Israel | |
| Britvin et al. (2021) |
| Britvin et al. (2021) +1 other reference |
Morocco | |
| Slabic (2022) |
Russia (TL) | |
| Britvin et al. (2020) |
Quick NavTopAbout KepleriteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Aravaite type locality, Hatrurim Basin, Tamar Regional Council, Beersheba Subdistrict, Southern District, Israel