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Johnkoivulaite-(Cs)
A valid IMA mineral species
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John I. Koivula
Formula:
Cs[Be2B]Mg2Si6O18
Colour:
Grayish violet
Lustre:
Vitreous
Hardness:
7½
Specific Gravity:
3.01
Crystal System:
Hexagonal
Member of:
Name:
Named in honour of John Ilmarii Koivula (b. 1949, Spokane, Washington, USA), GIA (Gemological Institute of America) researcher, for his many contributions in gemstone research (especially inclusions in gemstones) and photomicrography. He coathored the books 'Photoatlas of Inclusions in Gemstones' (three volumes) and 'The Microworld of Diamonds'.
Type Locality:
Isostructural with:
Unique combination of elements.
"This mineral is especially unique due to the strong pleochroism it shows from deep violet to nearly colorless when observed with polarized light".
When compared with beryl, it has most of Be substituted by B, Al substituted by Mg, and bears channel-residing, essential Cs.
In situ Raman spectroscopy and X-ray crystallography revealed a P6/mcc-to-P3c1 (second-order) phase transition on isothermal compression at the critical transition pressure Pc = 4.13 ± 0.07 GPa.
"This mineral is especially unique due to the strong pleochroism it shows from deep violet to nearly colorless when observed with polarized light".
When compared with beryl, it has most of Be substituted by B, Al substituted by Mg, and bears channel-residing, essential Cs.
In situ Raman spectroscopy and X-ray crystallography revealed a P6/mcc-to-P3c1 (second-order) phase transition on isothermal compression at the critical transition pressure Pc = 4.13 ± 0.07 GPa.
Unique Identifiers
Mindat ID:
53764
Long-form identifier:
mindat:1:1:53764:3
IMA Classification of Johnkoivulaite-(Cs)
Approved
IMA status notes:
Renamed by the IMA
IMA Formula:
Cs(Be2B)Mg2(Si6O18)
Approval year:
2019
First published:
2021
Approval history:
Renamed from johnkoivulaite
Type description reference:
Palke, Aaron C., Henling, Lawrence M., Ma, Chi, Rossman, George R., Sun, Ziyin, Renfro, Nathan, Kampf, Anthony R., Thu, Kyaw, Myo, Nay, Wongrawang, Patcharee, Weeramonkhonlert, Vararut (2021) Johnkoivulaite, Cs(Be2B)Mg2Si6O18, a new mineral of the beryl group from the gem deposits of Mogok, Myanmar. American Mineralogist, 106 (11) 1844-1851 doi:10.2138/am-2021-7785
Classification of Johnkoivulaite-(Cs)
9.CJ.05
9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions
9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions
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 |
|---|---|---|
| Joh | 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 Johnkoivulaite-(Cs)
Vitreous
Transparency:
Transparent
Colour:
Grayish violet
Hardness:
7½ on Mohs scale
Comment:
ca.
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
None
Fracture:
Conchoidal
Density:
3.01(10) g/cm3 (Measured) 3.117 g/cm3 (Calculated)
Optical Data of Johnkoivulaite-(Cs)
Type:
Uniaxial (-)
RI values:
nω = 1.607(1) nε = 1.605(1)
Max. Birefringence:
δ = 0.002
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:
Moderate (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:
Strong
Comments:
deep violet (E||c) to nearly colorless (E┴c)
Chemistry of Johnkoivulaite-(Cs)
Mindat Formula:
Cs[Be2B]Mg2Si6O18
Element Weights:
Crystallography of Johnkoivulaite-(Cs)
Crystal System:
Hexagonal
Class (H-M):
6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mcc
Setting:
P6/mcc
Cell Parameters:
a = 9.469(2) Å, c = 9.033(2) Å
Ratio:
a:c = 1 : 0.954
Unit Cell V:
701.5 ų
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.268 Å | (100) |
| 3.099 Å | (19) |
| 3.036 Å | (43) |
| 2.932 Å | (41) |
| 2.733 Å | (14) |
| 1.789 Å | (14) |
| 1.741 Å | (14) |
| 1.664 Å | (12) |
Reference:
Palke, Aaron C., Henling, Lawrence M., Ma, Chi, Rossman, George R., Sun, Ziyin, Renfro, Nathan, Kampf, Anthony R., Thu, Kyaw, Myo, Nay, Wongrawang, Patcharee, Weeramonkhonlert, Vararut (2021) Johnkoivulaite, Cs(Be2B)Mg2Si6O18, a new mineral of the beryl group from the gem deposits of Mogok, Myanmar. American Mineralogist, 106 (11) 1844-1851 doi:10.2138/am-2021-7785
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Johnkoivulaite-(Cs)
General Appearance of Type Material:
A single, irregularly shaped crystal, ca. 5.8×5.7×5.5 mm in size; geometric growth patterns observable.
Place of Conservation of Type Material:
In the mineralogical collections of the Gemological Museum, Gemological Institute of America, 5355 Armada Drive, Carlsbad, CA 92008, USA, catalogue number 41653
Geological Setting of Type Material:
Alluvial deposit.
Reference:
Palke, Aaron C., Henling, Lawrence M., Ma, Chi, Rossman, George R., Sun, Ziyin, Renfro, Nathan, Kampf, Anthony R., Thu, Kyaw, Myo, Nay, Wongrawang, Patcharee, Weeramonkhonlert, Vararut (2021) Johnkoivulaite, Cs(Be2B)Mg2Si6O18, a new mineral of the beryl group from the gem deposits of Mogok, Myanmar. American Mineralogist, 106 (11) 1844-1851 doi:10.2138/am-2021-7785
Other Language Names for Johnkoivulaite-(Cs)
Dutch:Johnkoivulaiet
German:Johnkoivulait
Relationship of Johnkoivulaite-(Cs) to other Species
Member of:
Other Members of Beryl Group:
| Bazzite | Be3Sc2(Si6O18) | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Beryl | Be3Al2(Si6O18) | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Pezzottaite-(Cs) | Cs(Be2Li)Al2(Si6O18) | Trig. 3 : R3 |
| Stoppaniite | Be3Fe3+2(Si6O18) · H2O | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
Related Minerals - Strunz-mindat Grouping
| 9.CJ. | Zolotarevite | Na5Zr[Si6O15(OH)3] · 3H2O |
| 9.CJ. | 'Avdeevite' | NaAl4(Be5Li)(Si6O18)2(H2O)1-2 |
| 9.CJ. | 'Beryllocordierite-Na' | NaMg4(Al5Be)(AlSi5O18)2 · 2H2O |
| 9.CJ. | Sachanbińskiite | NaMn4(Al5Be)(AlSi5O18)2 · 2H2O |
| 9.CJ. | Nakkaalaaqite | K2[Na3Ca]LiCa2Ti2Be4Si12O38 |
| 9.CJ.05 | Beryl | Be3Al2(Si6O18) |
| 9.CJ.05 | Bazzite | Be3Sc2(Si6O18) |
| 9.CJ.05 | Ferroindialite | (Fe2+,Mg)2Al4Si5O18 |
| 9.CJ.05 va | 'Vorobyevite' | Be3Al2(Si6O18) |
| 9.CJ.05 | Stoppaniite | Be3Fe3+2(Si6O18) · H2O |
| 9.CJ.05 | Indialite | Mg2Al3(AlSi5O18) |
| 9.CJ.10 | Sekaninaite | Fe2+2Al4Si5O18 |
| 9.CJ.10 | Cordierite | Mg2Al4Si5O18 |
| 9.CJ.15a | Zirsinalite | Na6(Ca,Mn2+,Fe2+)Zr(Si6O18) |
| 9.CJ.15a | Kapustinite | Na6ZrSi6O16(OH)2 |
| 9.CJ.15a | Townendite | Na8ZrSi6O18 |
| 9.CJ.15a | Combeite | Na4.5Ca3.5Si6O17.5(OH)0.5 |
| 9.CJ.15a | Kazakovite | Na6Mn2+Ti(Si6O18) |
| 9.CJ.15a | Tisinalite | Na3H3(Mn,Ca,Fe)TiSi6(O,OH)18 · 2H2O |
| 9.CJ.15a | Lovozerite | Na2Ca(Zr,Ti)(Si6O12)[(OH)4O2] · H2O |
| 9.CJ.15a | Litvinskite | Na2(◻,Na,Mn)ZrSi6O12(OH,O)6 |
| 9.CJ.15c | Koashvite | Na6(Ca,Mn)(Ti,Fe)Si6O18 · H2O |
| 9.CJ.15b | Imandrite | Na12Ca3Fe3+2(Si6O18)2 |
| 9.CJ.25 | Baratovite | KCa7(Ti,Zr)2Li3Si12O36F2 |
| 9.CJ.25 | Aleksandrovite | KCa7Sn2Li3Si12O36F2 |
| 9.CJ.25 | Katayamalite | KLi3Ca7Ti2(SiO3)12(OH)2 |
| 9.CJ.30 | Dioptase | CuSiO3 · H2O |
| 9.CJ.35 | Kostylevite | K2Zr(Si3O9) · H2O |
| 9.CJ.40 | Petarasite | Na5Zr2(Si6O18)(Cl,OH) · 2H2O |
| 9.CJ.45 | Gerenite-(Y) | (Ca,Na)2(Y,REE)3Si6O18 · 2H2O |
| 9.CJ.50 | Odintsovite | K2Na4Ca3Ti2Be4Si12O38 |
| 9.CJ.55 | Mathewrogersite | Pb7FeAl3GeSi12O36(OH,H2O)6 |
| 9.CJ.60 | Pezzottaite-(Cs) | Cs(Be2Li)Al2(Si6O18) |
Fluorescence of Johnkoivulaite-(Cs)
none
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 Johnkoivulaite-(Cs)
mindat.org URL:
https://www.mindat.org/min-53764.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Johnkoivulaite-(Cs)
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2019) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) NEWSLETTER 51. European Journal of Mineralogy, 31 (5-6) 1099-1104 doi:10.1127/ejm/2019/0031-2894
Palke, Aaron C., Henling, Lawrence M., Ma, Chi, Rossman, George R., Sun, Ziyin, Renfro, Nathan, Kampf, Anthony R., Thu, Kyaw, Myo, Nay, Wongrawang, Patcharee, Weeramonkhonlert, Vararut (2021) Johnkoivulaite, Cs(Be2B)Mg2Si6O18, a new mineral of the beryl group from the gem deposits of Mogok, Myanmar. American Mineralogist, 106 (11) 1844-1851 doi:10.2138/am-2021-7785
Localities for Johnkoivulaite-(Cs)
Showing 2 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.
Myanmar | |
| www.gia.edu (2021) |
| Miyawaki et al. (2019) |