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Megakalsilite

A valid IMA mineral species

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Discuss Megakalsilite

Edit Megakalsilite Add Synonym Edit CIF structures Clear Cache

Formula:

KAlSiO₄

Colour:

Colourless

Lustre:

Vitreous

Hardness:

Specific Gravity:

2.58

Crystal System:

Hexagonal

Name:

Named in allusion to the size of the Z value since it shares the same chemical formula with kalsilite, but its unit cell is 12 times larger.

Type Locality:

ⓘ Koashva Open Pit, Koashva Mt, Murmansk Oblast, Russia

Dimorph of:

Kalsilite

This page provides mineralogical data about Megakalsilite.

Hide all sections | Show all sections

Unique IdentifiersHide

Mindat ID:

10655

Long-form identifier:

mindat:1:1:10655:9

IMA Classification of MegakalsiliteHide

IMA status:

Approved

Approval year:

2001

Classification of MegakalsiliteHide

Strunz-mindat (2026):

9.FA.05

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H₂O
A : Tektosilicates without additional non-tetrahedral anions

Mineral SymbolsHide

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
Mks	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 MegakalsiliteHide

Lustre:

Vitreous

Transparency:

Transparent

Colour:

Colourless

Streak:

White

Hardness:

6 on Mohs scale

Tenacity:

Brittle

Cleavage:

None Observed

Fracture:

Conchoidal

Density:

2.58(2) g/cm³ (Measured) 2.62 g/cm³ (Calculated)

Optical Data of MegakalsiliteHide

Type:

Uniaxial (-)

RI values:

n_ω = 1.538(1) n_ε = 1.531(1)

Max. Birefringence:

δ = 0.007
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.

Thickness: 30 µm Order divisions

Rotation:

Surface Relief:

None to Very Low
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.

Focus:

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.

Thickness: 30 µm

Pleochroism:

Non-pleochroic

Chemistry of MegakalsiliteHide

Mindat Formula:

KAlSiO₄

Element Weights:

Element	% weight
O	40.463 %
K	24.720 %
Si	17.757 %
Al	17.059 %

Calculated from ideal end-member formula.

Elements listed:

Al, K, O, Si - search for minerals with similar chemistry

Crystallography of MegakalsiliteHide

Crystal System:

Hexagonal

Class (H-M):

6 - Pyramidal

Space Group:

P6₃

Cell Parameters:

a = 18.1111(8) Å, c = 8.4619(4) Å

Ratio:

a:c = 1 : 0.467

Unit Cell V:

2,403.74 Å³ (Calculated from Unit Cell)

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4

View
CIF File Best | x | y | z | a | b | c

Rotation
Stop | Start

Labels
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0005778	Megakalsilite	Khomyakov A P, Nechelyustov G N, Sokolova E V, Bonaccorsi E, Merlino S, Pasero M (2002) Megakalsilite, a new polymorph of KAlSiO4 from the Khibina alkaline massif, Kola Peninsula, Russia: mineral description and crystal structure The Canadian Mineralogist 40 961-970		2002	Khibina alkaline massif, Kola Peninsula, Russia	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Megakalsilite'
loop_
_publ_author_name
'Khomyakov A P'
'Nechelyustov G N'
'Sokolova E V'
'Bonaccorsi E'
'Merlino S'
'Pasero M'
_journal_name_full 'The Canadian Mineralogist'
_journal_volume 40 
_journal_year 2002
_journal_page_first 961
_journal_page_last 970
_publ_section_title
;
 Megakalsilite, a new polymorph of KAlSiO4 from the Khibina alkaline massif,
 Kola Peninsula, Russia: mineral description and crystal structure
;
_database_code_amcsd 0005778
_chemical_compound_source 'Khibina alkaline massif, Kola Peninsula, Russia'
_chemical_formula_sum 'Si Al K O4'
_cell_length_a 18.1111
_cell_length_b 18.1111
_cell_length_c 8.4619
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 120
_cell_volume 2403.743
_exptl_crystal_density_diffrn      2.622
_symmetry_space_group_name_H-M 'P 63'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x-y,x,1/2+z'
  '-y,x-y,z'
  '-x,-y,1/2+z'
  '-x+y,-x,z'
  'y,-x+y,1/2+z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Si(1)   0.83210   0.84060   0.19390   0.01100
Si(2)   0.66550   0.66520   0.79390   0.01060
Si(3)   0.65780   0.49400   0.17840   0.01110
Si(4)   0.50390   0.67750   0.17780   0.01160
Al(1)   0.83030   0.83810   0.81140   0.01080
Al(2)   0.66830   0.66820   0.18340   0.01100
Al(3)   0.65540   0.49150   0.79610   0.01090
Al(4)   0.50140   0.67610   0.79620   0.01100
K(1)   0.00000   0.00000   0.48620   0.02010
K(2)   0.66667   0.33333   0.50520   0.02080
K(3)   0.33333   0.66667   0.50480   0.02170
K(4)   0.47760   0.00470   0.49160   0.02300
K(5)   0.66650   0.81260   0.49460   0.02350
K(6)   0.80490   0.66750   0.49560   0.02330
O(1)   0.81610   0.85330   0.01010   0.01750
O(2)   0.66990   0.66500   0.98240   0.01980
O(3)   0.62720   0.47780   0.99510   0.01550
O(4)   0.51640   0.70650   0.99400   0.01710
O(5)   0.93080   0.86710   0.21780   0.01720
O(6)   0.73650   0.46760   0.77140   0.01630
O(7)   0.80090   0.39600   0.27240   0.01510
O(8)   0.90750   0.80840   0.79990   0.01830
O(9)   0.52500   0.76630   0.68520   0.01780
O(10)   0.43610   0.57710   0.18950   0.01930
O(11)   0.77020   0.74200   0.25070   0.01550
O(12)   0.89810   0.59480   0.75190   0.01600
O(13)   0.92560   0.35850   0.25580   0.01510
O(14)   0.35870   0.92970   0.73380   0.01610
O(15)   0.59440   0.90660   0.22530   0.01550
O(16)   0.73480   0.75840   0.72580   0.01680
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Si(1) 0.01080 0.00990 0.01190 0.00490 -0.00060 0.00070
Si(2) 0.01060 0.01040 0.01090 0.00520 -0.00070 0.00040
Si(3) 0.01100 0.01020 0.01200 0.00520 0.00100 -0.00040
Si(4) 0.01180 0.01030 0.01260 0.00550 0.00010 -0.00160
Al(1) 0.01060 0.01060 0.01120 0.00520 0.00010 0.00170
Al(2) 0.01150 0.01080 0.01070 0.00550 -0.00020 0.00020
Al(3) 0.01220 0.01110 0.01050 0.00660 0.00020 -0.00010
Al(4) 0.01020 0.01040 0.01200 0.00500 0.00090 0.00060
K(1) 0.02060 0.02060 0.01920 0.01030 0.00000 0.00000
K(2) 0.02040 0.02040 0.02180 0.01020 0.00000 0.00000
K(3) 0.02090 0.02090 0.02330 0.01050 0.00000 0.00000
K(4) 0.02910 0.02130 0.02080 0.01410 -0.00070 0.00210
K(5) 0.02380 0.02640 0.01990 0.01230 0.00230 0.00070
K(6) 0.02290 0.02290 0.02400 0.01130 0.00390 0.00720
O(1) 0.01880 0.02000 0.01500 0.01060 -0.00110 -0.00080
O(2) 0.02780 0.02010 0.01210 0.01250 -0.00030 -0.00150
O(3) 0.01500 0.01710 0.01430 0.00780 -0.00030 0.00250
O(4) 0.02030 0.01590 0.01350 0.00790 0.00030 -0.00230
O(5) 0.01300 0.01670 0.02210 0.00740 -0.00220 0.00400
O(6) 0.01310 0.01670 0.02040 0.00830 0.00620 0.00360
O(7) 0.01520 0.01150 0.01930 0.00730 0.00360 -0.00060
O(8) 0.01990 0.02310 0.01660 0.01420 0.00530 0.00380
O(9) 0.01870 0.01880 0.02020 0.01270 0.00720 0.00650
O(10) 0.01980 0.01160 0.02270 0.00490 0.00520 -0.00110
O(11) 0.01480 0.01280 0.01730 0.00590 -0.00430 0.00020
O(12) 0.01380 0.01620 0.01370 0.00420 0.00240 -0.00280
O(13) 0.01560 0.02280 0.01190 0.01350 -0.00290 -0.00280
O(14) 0.01900 0.01220 0.01880 0.00920 0.00400 0.00260
O(15) 0.01080 0.01310 0.01750 0.00230 0.00170 -0.00390
O(16) 0.01720 0.01500 0.01590 0.00620 -0.00240 -0.00050

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Stage 4b: Highly evolved igneous rocks	>3.0
35 : Ultra-alkali and agpaitic igneous rocks

Type Occurrence of MegakalsiliteHide

Type Locality:

ⓘ Koashva Open Pit, Koashva Mt, Murmansk Oblast, Russia

General Appearance of Type Material:

irregularly shaped grain 2 -3 mm across,

Place of Conservation of Type Material:

Fersman Mineralogical Museum, catalogue #2624/1, Russian Academy of Sciences, in Moscow, Russia.

Geological Setting of Type Material:

Hyperagpaitic pegmatite in ijolite–urtite, near their contact with apatite–nepheline rocks.

Associated Minerals at Type Locality:

Aegirine	Belovite-(Ce)	Cancrinite	Fluorcaphite	Galena
K Feldspar	Lemmleinite-K	Lomonosovite	Lovozerite	Nacaphite
Natrite	Natrolite	Pectolite	Phlogopite	Sodalite
Sphalerite	Umbite

Synonyms of MegakalsiliteHide

IMA2001-008

Other Language Names for MegakalsiliteHide

Dutch:Megakalsiliet

German:Megakalsilit

Russian:Мегакальсилит

Simplified Chinese:梅钾霞石

Spanish:Megakalsilita

Traditional Chinese:梅鉀霞石

Related Minerals - Strunz-mindat Grouping Hide

9.FA.	Bonaccorsiite	KK₂Na₃(Al₆Si₃₆)O₈₄	Hex. 6/mmm(6/m2/m2/m) : P6/mcc
9.FA.	Hexacelsian	BaAl₂Si₂O₈	Hex. 6/mmm(6/m2/m2/m) : P6₃/mcm
9.FA.	Wodegongjieite	KCa₃(Al₇Si₉)O₃₂	Hex. 6/mmm(6/m2/m2/m) : P6/mcc
9.FA.05	Panunzite	(K,Na)AlSiO₄	Hex. 6 : P6₃
9.FA.05	Yoshiokaite	(Ca,Na)[Al(Al,Si)O₄]	Trig. 3 : P3
9.FA.05	Nepheline	Na₃K(Al₄Si₄O₁₆)	Hex. 6 : P6₃
9.FA.05	Trinepheline	NaAlSiO₄	Hex. 6 : P6₁
9.FA.05	Davidsmithite	(Ca,◻)₂Na₆Al₈Si₈O₃₂	Hex. 6 : P6₃
9.FA.05	Kaliophilite	KAlSiO₄	Trig. 3 : P3
9.FA.05	Kalsilite	KAlSiO₄	Hex. 622 : P6₃22
9.FA.05	'Carnegieite'	NaAlSiO₄	Tric.
9.FA.05	Trikalsilite	K₂NaAl₃(SiO₄)₃	Hex. 6 : P6₃
9.FA.10	Malinkoite	NaBSiO₄	Hex. 6 : P6₃
9.FA.15	Virgilite	LiAlSi₂O₆	Hex. 622 : P6₂22
9.FA.25	Lisitsynite	KBSi₂O₆	Orth. 222 : P222
9.FA.30	Ferrisanidine	K[Fe³⁺Si₃O₈]	Mon. 2/m : B2/m
9.FA.30	Buddingtonite	(NH₄)(AlSi₃O₈)	Mon. 2 : P2₁
9.FA.30	Rubicline	Rb(AlSi₃O₈)	Mon. 2/m : B2/m
9.FA.30	'Monalbite'	NaAlSi₃O₈	Mon. 2/m : B2/m
9.FA.30	Microcline	K(AlSi₃O₈)	Tric. 1
9.FA.30 va	'Germanate-celsian'	BaAl₂Ge₂O₈
9.FA.30	Celsian	Ba(Al₂Si₂O₈)	Mon. 2/m
9.FA.30	Sanidine	K(AlSi₃O₈)	Mon. 2/m : B2/m
9.FA.30	Orthoclase	K(AlSi₃O₈)	Mon. 2/m : B2/m
9.FA.35	Reedmergnerite	NaBSi₃O₈	Tric. 1 : P1
9.FA.35	Albite	Na(AlSi₃O₈)	Tric. 1
9.FA.35	Anorthite	Ca(Al₂Si₂O₈)	Tric. 1 : P1
9.FA.40	Paracelsian	Ba(Al₂Si₂O₈)	Mon. 2/m : P2₁/b
9.FA.45	Svyatoslavite	Ca(Al₂Si₂O₈)	Mon. 2 : P2₁
9.FA.45	Kumdykolite	Na(AlSi₃O₈)	Orth. mmm(2/m2/m2/m) : Pnnm
9.FA.50	Slawsonite	Sr(Al₂Si₂O₈)	Mon. 2/m : P2₁/b
9.FA.55	Lisetite	CaNa₂Al₄Si₄O₁₆	Orth. mm2
9.FA.60	Stronalsite	Na₂SrAl₄Si₄O₁₆	Orth.
9.FA.60	Banalsite	Na₂BaAl₄Si₄O₁₆	Orth. mm2 : Iba2
9.FA.65	Maleevite	BaB₂Si₂O₈	Orth. mmm(2/m2/m2/m) : Pnma
9.FA.65	Pekovite	SrB₂Si₂O₈	Orth. mmm(2/m2/m2/m) : Pnma
9.FA.65	Danburite	CaB₂Si₂O₈	Orth. mmm(2/m2/m2/m)
9.FA.70	Liebermannite	KAlSi₃O₈	Tet. 4/m : I4/m
9.FA.70	Lingunite	NaAlSi₃O₈	Tet. 4/m : I4/m
9.FA.70	Stöfflerite	CaAl₂Si₂O₈	Tet. 4/m : I4/m
9.FA.75	Pfaffenbergite	KNa₃(Al₄Si₁₂)O₃₂	Hex. 6/mmm(6/m2/m2/m) : P6/mcc
9.FA.75	Kokchetavite	K(AlSi₃O₈)	Hex. 6/mmm(6/m2/m2/m) : P6/mcc

RadioactivityHide

Radioactivity:

Element	% Content	Activity (Bq/kg)	Radiation Type
Uranium (U)	0.0000%	0	α, β, γ
Thorium (Th)	0.0000%	0	α, β, γ
Potassium (K)	24.7203%	7,663	β, γ

For comparison:

Banana: ~15 Bq per fruit
Granite: 1,000–3,000 Bq/kg
EU exemption limit: 10,000 Bq/kg

Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.

Interactive Simulator:

Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!

Mass of radioactive mineral:

Shielding material:

Activity: –

Distance	Dose rate	Risk
1 cm
10 cm
1 m

The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μ_shield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).

D = ((A_U × Γ_U) + (A_Th × Γ_Th) + (A_K × Γ_K)) / r² × μ_shield

Fluorescence of MegakalsiliteHide

In UV light:

pale whitish green

Other InformationHide

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 MegakalsiliteHide

mindat.org URL:

https://www.mindat.org/min-10655.html
Please feel free to link to this page.

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External Links:

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Mineral Dealers:

Buy from D. Joyce minerals

References for MegakalsiliteHide

Reference List:

McGuire, Meaghan Clark, Ivor Bull, and Geoffrey Mark Johnson. "Synthetic Megakalsilite via Hydrothermal Preparation." U.S. Patent Application 14/204,079, filed September 11, 2014.

Khomyakov, A. P., Nechelyustov, G. N., Sokolova, E., Bonaccorsi, E., Merlino, S., Pasero, M. (2002) Megakalsilite, a new polymorph of KAlSiO₄ from the Khibina Alkaline Massif, Kola Peninsula, Russia: mineral description and crystal structure. The Canadian Mineralogist, 40 (3) 961-970 doi:10.2113/gscanmin.40.3.961

Localities for MegakalsiliteHide

Showing 1 localities.

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.

Hide all sections | Show all sections

Locality ListHide

- 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.

Russia (TL)

Murmansk Oblast

Koashva Mt

ⓘ Koashva Open Pit (TL)

Can Min (2002) +1 other reference

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Megakalsilite

Unique IdentifiersHide

IMA Classification of MegakalsiliteHide

Classification of MegakalsiliteHide

Mineral SymbolsHide

Physical Properties of MegakalsiliteHide

Optical Data of MegakalsiliteHide

Chemistry of MegakalsiliteHide

Crystallography of MegakalsiliteHide

Crystal StructureHide

Geological EnvironmentHide

Type Occurrence of MegakalsiliteHide

Synonyms of MegakalsiliteHide

Other Language Names for MegakalsiliteHide

Related Minerals - Strunz-mindat GroupingHide

RadioactivityHide

Fluorescence of MegakalsiliteHide

Other InformationHide

Internet Links for MegakalsiliteHide

References for MegakalsiliteHide

Localities for MegakalsiliteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide