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:

High (positive)
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 biaxial acute bisectrix (Bxa) interference figure - the conoscopic view for a grain cut perpendicular to the acute bisectrix, using this mineral's 2V. The two small white dots mark the melatopes - the points where the two optic axes emerge - and are shown only when they fall within the field of view. The coloured bands are isochromatics, and the dark bands are isogyres.

Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.

Thickness: 30 µm

Stage rotation: 0°

Dispersion:

r < v weak

Optical Extinction:

X = a, Y = b, Z = c.

Pleochroism:

Visible

Comments:

Z = lavender, X = pale lavender, Y = colorless.

Comments:

Absorption: Z > X > Y.

Chemistry of MagbasiteHide

Mindat Formula:

KBaFe³⁺Mg₇Si₈O₂₂(OH)₂F₆

Originally assumed to be considerably Sc-bearing.

Element Weights:

Element	% weight
O	34.069 %
Si	19.935 %
Mg	15.095 %
Ba	12.184 %
F	10.114 %
Fe	4.955 %
K	3.469 %
H	0.179 %

Calculated from ideal end-member formula.

Elements listed:

Ba, F, Fe, H, K, Mg, O, Si - search for minerals with similar chemistry

Common Impurities:

Crystallography of MagbasiteHide

Crystal System:

Orthorhombic

Class (H-M):

mmm(2/m2/m2/m) - Dipyramidal

Space Group:

Cmma

Cell Parameters:

a = 18.9506(3) Å, b = 22.5045(3) Å, c = 5.2780(1) Å

Ratio:

a:b:c = 0.842 : 1 : 0.235

Unit Cell V:

2250.93 Å³

Morphology:

As bundles of prismatic and acicular crystals

Comment:

Space group Cmme (Cmma).

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
Console Off | On | Grey | Yellow

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)
0020127	Magbasite	Welch M D, Mitchell R H, Kampf A R, Chakhmouradian, Smith D, Carter M (2014) Crystal structure and topological affinities of magbasite, KBaFe3+Mg7Si8O22(OH)2F6: a trellis structure related to amphibole and carpholite Mineralogical Magazine 78 29-45		2014	Eldor carbonatite complex, Labrador Trough, Quebec, Canada	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Magbasite'
loop_
_publ_author_name
'Welch M D'
'Mitchell R H'
'Kampf A R'
'Chakhmouradian'
'Smith D'
'Carter M'
_journal_name_full 'Mineralogical Magazine'
_journal_volume 78 
_journal_year 2014
_journal_page_first 29
_journal_page_last 45
_publ_section_title
;
 Crystal structure and topological affinities of magbasite,
 KBaFe3+Mg7Si8O22(OH)2F6: a trellis structure related to amphibole and carpholite
;
_database_code_amcsd 0020127
_chemical_compound_source 'Eldor carbonatite complex, Labrador Trough, Quebec, Canada'
_chemical_formula_sum 'K Ba Fe1.633 Mg6.267 Al.1 Si8 O24 H2 F6'
_cell_length_a 18.9506
_cell_length_b 22.5045
_cell_length_c 5.2780
_cell_angle_alpha 90
_cell_angle_beta 90
_cell_angle_gamma 90
_cell_volume 2250.928
_exptl_crystal_density_diffrn      3.386
_symmetry_space_group_name_H-M 'C m m a'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  '1/2+x,-y,z'
  '+x,1/2-y,z'
  '1/2-x,y,-z'
  '-x,1/2+y,-z'
  '-x,y,z'
  '1/2-x,1/2+y,z'
  'x,-y,-z'
  '1/2+x,1/2-y,-z'
  '1/2+x,y,-z'
  '+x,1/2+y,-z'
  '1/2-x,-y,z'
  '-x,1/2-y,z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
KA   0.50000   0.25000   0.16710   1.00000   0.02180
BaB   0.25000   0.00000   0.00000   1.00000   0.01420
Fe1   0.25000   0.17858   0.00000   0.02600   0.00820
Mg1   0.25000   0.17858   0.00000   0.97400   0.00820
Mg2   0.25000   0.10953   0.50000   0.96700   0.00860
Fe2   0.25000   0.10953   0.50000   0.03300   0.00860
Mg3   0.25000   0.25000   0.50000   0.99700   0.00740
Fe3   0.25000   0.25000   0.50000   0.00300   0.00740
Mg4   0.08910   0.00000   0.50000   0.69400   0.00990
Fe4   0.08910   0.00000   0.50000   0.30600   0.00990
Al5   0.00000   0.00000   0.00000   0.10000   0.00780
Fe5   0.00000   0.00000   0.00000   0.90000   0.00780
Si1   0.10920   0.18227   0.33473   1.00000   0.00690
Si2   0.39170   0.11413   0.16654   1.00000   0.00720
O2   0.07852   0.25000   0.33140   1.00000   0.01100
O3   0.19395   0.18251   0.33430   1.00000   0.00840
O4   0.30704   0.11463   0.17270   1.00000   0.00910
O5   0.42215   0.15204   0.41100   1.00000   0.01090
O6   0.07865   0.15062   0.08150   1.00000   0.01010
O7   0.42252   0.04791   0.17180   1.00000   0.01010
O1   0.00000   0.04359   0.32200   1.00000   0.01090
H   0.00000   0.07700   0.31300   1.00000   0.05000
F1   0.30215   0.25000   0.16430   1.00000   0.01130
F2   0.17678   0.05164   0.37280   1.00000   0.01610
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
KA 0.02530 0.01940 0.02090 0.00000 0.00000 0.00000
BaB 0.02310 0.00886 0.01064 0.00000 0.00000 0.00000
Fe1 0.00970 0.00750 0.00750 0.00000 0.00030 0.00000
Mg1 0.00970 0.00750 0.00750 0.00000 0.00030 0.00000
Mg2 0.01020 0.00780 0.00780 0.00000 0.00130 0.00000
Fe2 0.01020 0.00780 0.00780 0.00000 0.00130 0.00000
Mg3 0.00900 0.00660 0.00650 0.00000 -0.00070 0.00000
Fe3 0.00900 0.00660 0.00650 0.00000 -0.00070 0.00000
Mg4 0.01130 0.00990 0.00840 -0.00210 0.00000 0.00000
Fe4 0.01130 0.00990 0.00840 -0.00210 0.00000 0.00000
Al5 0.00990 0.00680 0.00670 0.00000 0.00000 0.00000
Fe5 0.00990 0.00680 0.00670 0.00000 0.00000 0.00000
Si1 0.00810 0.00590 0.00670 -0.00020 0.00010 -0.00010
Si2 0.00830 0.00640 0.00680 0.00070 0.00000 0.00020
O2 0.01120 0.00590 0.01590 0.00000 -0.00040 0.00000
O3 0.00900 0.00810 0.00820 -0.00070 0.00000 -0.00060
O4 0.00940 0.00880 0.00900 0.00090 0.00050 0.00040
O5 0.01060 0.01200 0.01000 -0.00010 0.00050 -0.00320
O6 0.01020 0.01130 0.00880 -0.00010 -0.00010 -0.00290
O7 0.01210 0.00770 0.01040 0.00260 0.00070 0.00070
O1 0.01590 0.00600 0.01080 0.00000 0.00000 -0.00120
F1 0.01300 0.01030 0.01060 0.00000 0.00120 0.00000
F2 0.01910 0.01410 0.01530 -0.00430 0.00130 -0.00260

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
2.572 Å	(100)
2.991 Å	(68)
3.546 Å	(47)
2.416 Å	(41)
2.848 Å	(39)
2.306 Å	(38)
1.6336 Å	(38)

Comments:

Eldor carbonatite complex, Quebec, Canada. Data from Welch et al. (2014).

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
Near-surface Processes
23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47)
Stage 4b: Highly evolved igneous rocks	>3.0
36 : Carbonatites, kimberlites, and related igneous rocks

Type Occurrence of MagbasiteHide

Type Locality:

ⓘ Bayan Obo deposit, Bayan Obo mining district, Baotou City, Inner Mongolia, China

General Appearance of Type Material:

Fan-shaped fine acicular and felt-like deposits up to 5 mm in size, somewhat resembling tremolite.

Place of Conservation of Type Material:

Ferman Mineralogical Museum, Moscow, Russia, number 73225 (type).

Geological Setting of Type Material:

Associated with alkalic barkevitic granosyenites occurring in dolomites.

Associated Minerals at Type Locality:

Fluorite

Baryte

Parisite

Other Language Names for MagbasiteHide

Dutch:Magbasiet

German:Magbasit

Russian:Магбасит

Spanish:Magbasita

Related Minerals - Strunz-mindat Grouping Hide

9.HA.	Shinichengite	Ca₅[BSi₂O₇(OH)₂]₂ · 6H₂O	Tric. 1 : P1
9.HA.	Kalyuzhnyite-(Ce)	NaKCaSrCeTi(Si₈O₂₁)OF(H₂O)₃	Mon. 2/m : P2/b
9.HA.	Moragite	Ca₃TiSi₂(Al₂Si)O₁₄	Trig. 32 : P321
9.HA.05	Ertixiite	Na₂Si₄O₉	Iso.
9.HA.10	Kenyaite	Na₂Si₂₂O₄₁(OH)₈ · 6H₂O	Mon.
9.HA.20	Wawayandaite	Ca₆Mn₂BBe₉Si₆O₂₃(OH,Cl)₁₅	Mon.
9.HA.35	Demagistrisite	BaCa₂Mn³⁺₄(Si₃O₁₀)(Si₂O₇)(OH)₄ · 3H₂O	Orth. mm2 : Amm2
9.HA.37	Donwilhelmsite	CaAl₄Si₂O₁₁	Hex. 6/mmm(6/m2/m2/m) : P6₃/mmc
9.HA.40	Kasatkinite	Ba₂Ca₈B₅Si₈O₃₂(OH)₃ · 6H₂O	Mon.
9.HA.40	'Igumnovite'	Ca₃Al₂[SiO₄]₂[◻Cl₄]	Iso.
9.HA.42	Paqueite	Ca₃TiSi₂(Al,Ti,Si)₃O₁₄	Trig. 32 : P321
9.HA.42	Qeltite	Ca₃TiSi₂(Fe³⁺₂Si)O₁₄	Trig. 32 : P321
9.HA.45	Rippite	K₂(Nb,Ti)₂(Si₄O₁₂)O(O,F)	Tet.
9.HA.47	Zagamiite	CaAl₂Si_3.5O₁₁	Hex. 6/mmm(6/m2/m2/m) : P6₃/mmc
9.HA.50	Rudenkoite	Sr₃(Al_3.5Si_3.5)O₁₀(OH,O)₈Cl₂ · H₂O	Mon.
9.HA.50	'α-Carnegieite'	NaAlSiO₄
9.HA.52	'Atheriastite'	near Ca₅MgFeAl₆Si₈O₃₂ · 5H₂O
9.HA.55	'Foshallasite'	Ca₃[Si₂O₇] · 3H₂O(?)
9.HA.57	'Bhreckite'
9.HA.60	Nagelschmidtite	Ca₇(SiO₄)₂(PO₄)₂	Hex. 6 : P6₁
9.HA.65	Caryochroite	[Na(Sr_0.5Ca_0.5)Mg]₃[Fe³⁺₈Mn(Fe²⁺_0.5◻_0.5)]₁₀(Ti₂Si₁₂O₃₇)(OH)₁₄(H₂O)₃	Mon. 2/m
9.HA.70	Juanite	Ca₁₀Mg₄Al₂Si₁₁O₃₉ · 4H₂O or near	Orth.
9.HA.75	Tacharanite	Ca₁₂Al₂Si₁₈O₃₃(OH)₃₆	Mon.
9.HA.80	Oyelite	Ca₁₀Si₈B₂O₂₉ · 12.5H₂O	Tric. 1 : P1
9.HA.85	Denisovite	K_14+x(Ca,Na,Mn,Fe)₄₈[Si₆₀O₁₆₂]F₁₆(O_x,OH_4-x) · 2H₂O	Mon.
9.HA.90	Tiettaite	K₄Na₁₂Fe³⁺Si₁₆O₄₁(OH)₄ · 2H₂O	Orth. mmm(2/m2/m2/m) : Cmcm

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)	3.4690%	1,075	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

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 MagbasiteHide

mindat.org URL:

https://www.mindat.org/min-2531.html
Please feel free to link to this page.

Search Engines:

Look for Magbasite on Google

Look for Magbasite images on Google

Look for Magbasite on Bing

Look for Magbasite images on Bing

Look for Magbasite on DuckDuckGo

Look for Magbasite images on DuckDuckGo

Look for Magbasite in the Rock H. Currier Digital Library

External Links:

Look for Magbasite on Webmineral

Look for Magbasite on Wikipedia

Look for Magbasite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for MagbasiteHide

Reference List:

Semenov, I.E., Khomyakov, A.R., Bukova, A.V. (1965) Magbasite - New mineral. Doklady Akademii Nauk SSSR: 163(3): 718-719. (in Russian)

Fleischer, Michael (1966) New Mineral Names. American Mineralogist, 51 (3-4) 529-534

Association, International Mineralogical (1968) International Mineralogical Association: Commission on New Minerals and Mineral Names. Mineralogical Magazine and Journal of the Mineralogical Society, 36 (284). 1143-1145 doi:10.1180/minmag.1968.036.284.11

Smith, P. P. K. (1979) The observation of enantiomorphous domains in a natural maghemite. Contributions to Mineralogy and Petrology, 69 (3) 249-254 doi:10.1007/bf00372327

Welch, M.D., Mitchell, R.H., Kampf, A.R., Chakhmouradian, A.R., Smith, D., Carter, M. (2014) Crystal structure and topological affinities of magbasite, KBaFe3+Mg7Si8O22(OH)2F6: a trellis structure related to amphibole and carpholite. Mineralogical Magazine: 78: 29-45.

Camara, F.; Gagne, O. C.; Uvarova, Y.; Belakovskiy, D. I. (2014) New Mineral Names. American Mineralogist, 99 (11-12). 2437-2444 doi:10.2138/am-2014-653

(2020) Magbasite. Handbook of Mineralogy. Mineralogical Society of America

Localities for MagbasiteHide

Showing 4 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.


Canada
Québec Nord-du-Québec Nunavik ⓘ Eldor Carbonatite Complex (Eldor carbonatite)	Mitchell et al. (2017)
Ashram Zone ⓘ Ashram REE deposit	Mitchell et al. (2017)

China (TL)
Inner Mongolia Baotou City Bayan Obo mining district ⓘ Bayan Obo deposit (TL)	Semenov et al. (1965) +1 other reference
ⓘ Main pit	Xue et al. (2026)

Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 28, 2026 20:20:22 Page updated: August 25, 2026 11:52:24

Go to top of page

Magbasite

About MagbasiteHide

Unique IdentifiersHide

Similar NamesHide

IMA Classification of MagbasiteHide

Classification of MagbasiteHide

Mineral SymbolsHide

Physical Properties of MagbasiteHide

Optical Data of MagbasiteHide

Chemistry of MagbasiteHide

Crystallography of MagbasiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of MagbasiteHide

Other Language Names for MagbasiteHide

Related Minerals - Strunz-mindat GroupingHide

RadioactivityHide

Other InformationHide

Internet Links for MagbasiteHide

References for MagbasiteHide

Localities for MagbasiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide