Johnkoivulaite (original) (raw)

A valid IMA mineral species

Formula:

Cs[Be2B]Mg2Si6O18

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'.

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.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:53764:3

333a37a2-17b7-40b2-afb5-36e16c439630

IMA Classification of JohnkoivulaiteHide

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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 JohnkoivulaiteHide

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9.CJ.05

9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of JohnkoivulaiteHide

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Density:

3.01(10) g/cm3 (Measured) 3.117 g/cm3 (Calculated)

Optical Data of JohnkoivulaiteHide

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RI values:

_n_ω = 1.607(1) _n_ε = 1.605(1)

δ = 0.002

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Comments:

deep violet (E||c) to nearly colorless (E┴c)

Chemistry of JohnkoivulaiteHide

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Mindat Formula:

Cs[Be2B]Mg2Si6O18

Crystallography of JohnkoivulaiteHide

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Class (H-M):

6/m m m _(_6/_m_2/_m_2/m ) - Dihexagonal Dipyramidal

Cell Parameters:

a = 9.469(2) Å, c = 9.033(2) Å

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Type Occurrence of JohnkoivulaiteHide

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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:

Reference:

Palke, A.C., Henling, L.M., Ma, C., Rossman, G.R., Sun, Z., Renfro, N., Kampf, A.R., Thu, K., Myo, N., Wongrawang, P., Weeramonkhonlert, V. (2021): Johnkoivulaite, Cs(Be2B)Mg2Si6O18, a new mineral of the beryl group from the gem deposits of Mogok, Myanmar. American Mineralogist: 106: 1844-1851.

Relationship of Johnkoivulaite to other SpeciesHide

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Other Members of this group:

Related Minerals - Strunz-mindat GroupingHide

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Fluorescence of JohnkoivulaiteHide

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Other InformationHide

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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 JohnkoivulaiteHide

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References for JohnkoivulaiteHide

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Reference List:

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

Diego Gatta, G, Ende, Martin, Miloš, Sofija, Rotiroti, Nicola, Palke, Aaron C, Miletich, Ronald (2024) High-pressure behavior and structural transition of beryl-type johnkoivulaite, Cs (Be2B) Mg2Si6O18. American Mineralogist, 109 (1) 15-23

Localities for JohnkoivulaiteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.