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Keystoneite
A valid IMA mineral species
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About Keystoneite
Formula:
Mg0.5Ni2+Fe3+(Te4+O3)3 · 4.5H2O
Colour:
Golden yellow
Lustre:
Adamantine
Specific Gravity:
4.4 (Calculated)
Crystal System:
Hexagonal
Member of:
Name:
For the type locality.
Ni-analogue of kinichilite and zemannite. The Ni-Fe-analogue of ilirneyite.
Chemically and structurally related to wortupaite.
Chemically and structurally related to wortupaite.
Unique Identifiers
Mindat ID:
2192
Long-form identifier:
mindat:1:1:2192:6
IMA Classification of Keystoneite
Classification of Keystoneite
4.JM.05
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
M : Tellurites without additional anions, with H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
M : Tellurites without additional anions, with H2O
34.3.2.3
34 : SELENITES, TELLURITES AND SULFITES
3 : A2(XO3)3·xH2O
34 : SELENITES, TELLURITES AND SULFITES
3 : A2(XO3)3·xH2O
28.3.28
28 : Selenites, Selenates, Tellurites, and Tellurates
3 : Tellurites
28 : Selenites, Selenates, Tellurites, and Tellurates
3 : Tellurites
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 |
|---|---|---|
| Kys | 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 Keystoneite
Adamantine
Transparency:
Translucent
Colour:
Golden yellow
Streak:
Pale yellow-green
Density:
4.4 g/cm3 (Calculated)
Optical Data of Keystoneite
Type:
Uniaxial (+)
RI values:
nω = 1.85(1) nε = 1.99(1)
Max. Birefringence:
δ = 0.140
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 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.
Chemistry of Keystoneite
Mindat Formula:
Mg0.5Ni2+Fe3+(Te4+O3)3 · 4.5H2O
Element Weights:
Crystallography of Keystoneite
Crystal System:
Hexagonal
Class (H-M):
6 - Pyramidal
Space Group:
P63
Cell Parameters:
a = 9.3667(5) Å, c = 7.6173(3) Å
Ratio:
a:c = 1 : 0.813
Unit Cell V:
578.77 ų
Z:
2
Morphology:
Acicular hexagonal crystals, parallel aggregates and radiating sprays.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.12 Å | (90) |
| 4.05 Å | (80) |
| 2.952 Å | (50) |
| 2.838 Å | (50) |
| 2.774 Å | (100) |
| 1.720 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Keystoneite
Place of Conservation of Type Material:
Canadian Museum of Nature, Ottawa, Canada 56561
Geological Setting of Type Material:
Oxidation zone of a complex polymetallic hydrothermal deposit.
Synonyms of Keystoneite
Other Language Names for Keystoneite
Relationship of Keystoneite to other Species
Member of:
Other Members of Zemannite Group:
| Ilirneyite | Mg0.5ZnMn3+(Te4+O3)3 · 4.5H2O | Hex. 6/m : P63/m |
| Kinichilite | Mg0.5Mn2+Fe3+(Te4+O3)3 · 4.5H2O | Hex. 6/m : P63/m |
| Zemannite | Mg0.5ZnFe3+(Te4+O3)3 · 4.5H2O | Trig. 3 : P3 |
Common Associates
Associations Based on Photo Data:
| 5 photos of Keystoneite associated with Choloalite | (Cu,Sb)3(Pb,Ca)3(TeO3)6Cl |
| 5 photos of Keystoneite associated with Quartz | SiO2 |
| 1 photo of Keystoneite associated with Hessite | Ag2Te |
| 1 photo of Keystoneite associated with Native Gold | Au |
| 1 photo of Keystoneite associated with Altaite | PbTe |
| 1 photo of Keystoneite associated with Melonite | NiTe2 |
| 1 photo of Keystoneite associated with Petzite | Ag3AuTe2 |
Related Minerals - Strunz-mindat Grouping
| 4.JM. | Wortupaite | MgNi2+2(Te4+O3)3 · 3H2O |
| 4.JM. | Rudolfhermannite | Fe3+2(Te4+O3)3(H2O) |
| 4.JM.05 | Zemannite | Mg0.5ZnFe3+(Te4+O3)3 · 4.5H2O |
| 4.JM.05 | Kinichilite | Mg0.5Mn2+Fe3+(Te4+O3)3 · 4.5H2O |
| 4.JM.05 | Ilirneyite | Mg0.5ZnMn3+(Te4+O3)3 · 4.5H2O |
| 4.JM.10 | Emmonsite | Fe3+2(TeO3)3 · 2H2O |
| 4.JM.10 | Blakeite | Fe3+2[TeO3]3 (?) |
| 4.JM.15 | Graemite | Cu[TeO3] · H2O |
| 4.JM.20 | Telluromandarinoite | Fe3+2Te3O9 · 6H2O |
| 4.JM.20 | Teineite | Cu2+(Te4+O3) · 2H2O |
| 4.JM.25 | Millsite | Cu2+(Te4+O3) · 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 Keystoneite
mindat.org URL:
https://www.mindat.org/min-2192.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Keystoneite
Localities for Keystoneite
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.
Armenia | |
| Pavel M. Kartashov analytical data (2003) |
USA | |
| Roberts et al. (1994) +1 other reference |
| Eckel et al. (1997) +2 other references |
| Eckel et al. (1997) |
Quick NavTopAbout KeystoneiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
McAlpine Mine, Peñon Blanco Peak, Coulterville Mining District, Tuolumne County, California, USA