Bultfonteinite
A valid IMA mineral species - grandfathered
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About Bultfonteinite
Formula:
Ca2(HSiO4)F · H2O
Colour:
colourless, pink
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.73
Crystal System:
Triclinic
Name:
The mineral was first found by a miner named Cann in 1903
or 1904 on the 480-foot level of the Bultfontein mine at Kimberley. Named in 1932 by John Parry, Alpheus Fuller Williams, and Frederick Eugene Wright for the type locality at Bultfontein, Kimberly, Free State Province, South Africa. Pronounced bilt-von-tain-ite.
or 1904 on the 480-foot level of the Bultfontein mine at Kimberley. Named in 1932 by John Parry, Alpheus Fuller Williams, and Frederick Eugene Wright for the type locality at Bultfontein, Kimberly, Free State Province, South Africa. Pronounced bilt-von-tain-ite.
This page provides mineralogical data about Bultfonteinite.
Unique Identifiers
Mindat ID:
800
Long-form identifier:
mindat:1:1:800:8
IMA Classification of Bultfonteinite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca2[SiO3(OH)]F·H2O
First published:
1932
Classification of Bultfonteinite
9.AG.80
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
G : Nesosilicates with additional anions; cations in > [6] +- [6] coordination
52.4.7.2
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
4 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] and/or >[6] coordination
17.1.16
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
17 : Silicates Containing other Anions
1 : Silicates with fluoride (not containing Al)
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Bul | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Bul | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Bultfonteinite
Vitreous
Transparency:
Transparent
Colour:
Colourless, pink
Streak:
White
Hardness:
4½ on Mohs scale
Cleavage:
Distinct/Good
Good on {100} and {010}
Good on {100} and {010}
Fracture:
Conchoidal
Density:
2.73 g/cm3 (Measured) 2.74 g/cm3 (Calculated)
Optical Data of Bultfonteinite
Type:
Biaxial (+)
RI values:
nα = 1.587(2) nβ = 1.590(2) nγ = 1.597(2)
2V:
Measured: 70°
Max. Birefringence:
δ = 0.010
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 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.
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.
Dispersion:
r > v
Chemistry of Bultfonteinite
Mindat Formula:
Ca2(HSiO4)F · H2O
Element Weights:
Common Impurities:
B,Al,Na,P
Crystallography of Bultfonteinite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 10.99 Å, b = 8.18 Å, c = 5.67 Å
α = 93.95°, β = 91.32°, γ = 89.85°
α = 93.95°, β = 91.32°, γ = 89.85°
Ratio:
a:b:c = 1.344 : 1 : 0.693
Unit Cell V:
508.38 ų (Calculated from Unit Cell)
Z:
4
Twinning:
Interpenetrating on {100} and {010}; polysynthetic.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0018795 | Bultfonteinite | Biagioni C, Bonaccorsi E, Merlino S (2010) Crystal structure of bultfonteinite, Ca4[SiO3(OH)]2F2*2H2O, from N'chwaning II mine (Kalahari Manganese Field, Republic of South Africa) Atti della Societa Toscana di Scienze Naturali, Memorie, Serie A 115 9-15 | 2010 | N'chwaning II mine, South Africa | 0 | 293 | |
| 0009278 | Bultfonteinite | McIver E J (1963) The structure of bultfonteinite, Ca4Si2O10F2H6 Acta Crystallographica 16 551-558 |  | 1963 | Bultfontein mine, Kimberley, South Africa | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 1.93 Å | (100) |
| 8.12 Å | (60) |
| 2.92 Å | (60) |
| 2.88 Å | (60) |
| 2.037 Å | (50) |
| 4.06 Å | (40) |
| 3.50 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 7 : Ultramafic igneous rocks | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Type Occurrence of Bultfonteinite
General Appearance of Type Material:
As radiating prismatic acicular crystals and radial spherules, to 2 cm
Place of Conservation of Type Material:
Cambridge University, Cambridge; The Natural History Museum, London, England, 1928,78.
Geological Setting of Type Material:
a large "horse" of diabase and shale fragments in a kimberlite pipe
Associated Minerals at Type Locality:
Other Language Names for Bultfonteinite
Common Associates
Associations Based on Photo Data:
| 159 photos of Bultfonteinite associated with Olmiite | CaMn2+[SiO3(OH)](OH) |
| 64 photos of Bultfonteinite associated with Calcite | CaCO3 |
| 42 photos of Bultfonteinite associated with Xonotlite | Ca6(Si6O17)(OH)2 |
| 41 photos of Bultfonteinite associated with Jouravskite | Ca3Mn4+(SO4)(CO3)(OH)6 · 12H2O |
| 34 photos of Bultfonteinite associated with Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O |
| 26 photos of Bultfonteinite associated with Oyelite | Ca10Si8B2O29 · 12.5H2O |
| 13 photos of Bultfonteinite associated with Andradite | Ca3Fe3+2(SiO4)3 |
| 12 photos of Bultfonteinite associated with Datolite | CaB(SiO4)(OH) |
| 12 photos of Bultfonteinite associated with Poldervaartite | CaCa[SiO3(OH)](OH) |
| 8 photos of Bultfonteinite associated with Manganite | Mn3+O(OH) |
Related Minerals - Strunz-mindat Grouping
| 9.AG. | Aluminotaipingite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4F3 |
| 9.AG. | 'Ivanyukite-Na-T' | Na2Ti4(SiO4)3(OH)O3 · 7H2O |
| 9.AG. | 'Ivanyukite-Na-C' | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
| 9.AG. | Edgrewite | Ca9(SiO4)4F2 |
| 9.AG.02 | Gatedalite | ZrMn2+2Mn3+4SiO12 |
| 9.AG.05 | Abswurmbachite | CuMn3+6(SiO4)O8 |
| 9.AG.05 | Neltnerite | CaMn3+6(SiO4)O8 |
| 9.AG.05 | Skogbyite | Zr(Mg2Mn3+4)SiO12 |
| 9.AG.05 | Braunite | Mn2+Mn3+6(SiO4)O8 |
| 9.AG.05 | 'Braunite-II' | Ca(Mn3+,Fe)14(SiO4)O20 |
| 9.AG.10 | Långbanite | Mn2+4Mn3+9Sb5+O16(SiO4)2 |
| 9.AG.12 | Taipingite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3[SiO3(OH)]4F3 |
| 9.AG.15 | Żabińskiite | Ca[Al0.5(Ta,Nb)0.5)]O(SiO4) |
| 9.AG.15 | Titanite | CaTiO(SiO4) |
| 9.AG.15 | Vanadomalayaite | CaVO(SiO4) |
| 9.AG.15 | Natrotitanite | (Na0.5Y0.5)TiO(SiO4) |
| 9.AG.15 | Malayaite | CaSnO(SiO4) |
| 9.AG.20 | Ferricerite-(LaCa) | (La6Ca3)◻Fe3+(SiO4)3(SiO3OH)4(OH)3 |
| 9.AG.20 | Aluminocerite-(CeCa) | (Ce6Ca3)◻Al(SiO4)3[SiO3(OH)]4(OH)3 |
| 9.AG.20 | Cerite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3(SiO3OH)4(OH)3 |
| 9.AG.20 | Nipeiite-(Ce) | Ce9Fe3+(SiO4)6[SiO3(OH)](OH)3 |
| 9.AG.25 | 'Yftisite-(Y)' | (Y,Dy,Er)4(Ti,Sn)(SiO4)2O(F,OH)6 |
| 9.AG.25 | Mieite-(Y) | Y4Ti(SiO4)2O[F,(OH)]6 |
| 9.AG.25 | Trimounsite-(Y) | Y2Ti2(SiO4)O5 |
| 9.AG.30 | Sitinakite | KNa2Ti4(SiO4)2O5(OH) · 4H2O |
| 9.AG.35 | Kittatinnyite | Ca2Mn2Mn(SiO4)2(OH)4 · 9H2O |
| 9.AG.40b | Paranatisite | Na2Ti(SiO4)O |
| 9.AG.40a | Natisite | Na2Ti(SiO4)O |
| 9.AG.45 | Törnebohmite-(Ce) | Ce2Al(SiO4)2(OH) |
| 9.AG.45 | Törnebohmite-(La) | La2Al(SiO4)2(OH) |
| 9.AG.50 | Ivanyukite-Na | Na2Ti4(SiO4)3(OH)2O2 · 6H2O |
| 9.AG.50 | Ivanyukite-K | K2Ti4(SiO4)3(OH)2O2 · 9H2O |
| 9.AG.50 | Ivanyukite-Cu | CuTi4(SiO4)3(OH)2O2 · 7H2O |
| 9.AG.50 | Kuliokite-(Y) | Y4Al(SiO4)2(OH)2F5 |
| 9.AG.50 | Hydroxyledgrewite | Ca9(SiO4)4(OH)2 |
| 9.AG.52 | Ulfanderssonite-(Ce) | (Ce15Ca)Σ16Mg2(SiO4)10(SiO3OH)(OH,F)5Cl3 |
| 9.AG.55 | Chantalite | CaAl2(SiO4)(OH)4 |
| 9.AG.60 | Vuagnatite | CaAl(SiO4)(OH) |
| 9.AG.60 | Mozartite | CaMn3+(SiO4)(OH) |
| 9.AG.65 | Hatrurite | Ca3(SiO4)O |
| 9.AG.70 | Jasmundite | Ca11(SiO4)4O2S |
| 9.AG.75 | Afwillite | Ca3[SiO4][SiO2(OH)2] · 2H2O |
| 9.AG.85 | Zoltaiite | BaV4+2V3+12(SiO4)2O19 |
| 9.AG.90 | Tranquillityite | (Fe2+,Ca)8(Zr,Y)2Ti3(SiO4)3O12 |
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 Bultfonteinite
mindat.org URL:
https://www.mindat.org/min-800.html
Please feel free to link to this page.
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References for Bultfonteinite
Reference List:
Parry, John, Williams, Alpiieus F., Wright, F. E. (1932) On bultfonteinite, a new fluorine-bearing hydrous calcium silicate from South Africa. Mineralogical Magazine and Journal of the Mineralogical Society, 23 (138) 145-162 doi:10.1180/minmag.1932.023.138.01
Localities for Bultfonteinite
Showing 27 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.
Australia | |
| Henry (1999) |
Botswana | |
| Debswana Diamond Company Ltd |
Canada | |
| Anton R. Chakhmouradian and Roger H. Mitchell (2001) |
| Abersteiner et al. (2018) |
| Martin et al. (2023) |
China | |
| Ed Richard collection +1 other reference |
Germany | |
| Juroszek et al. (Ti 5 Fe) |
Japan | |
| Minakawa et al. (1986) |
| |
| Kusachi et al. (1991) +3 other references |
Jordan | |
| Anthony et al. (2016) |
| Fleurance et al. (2013) | |
| Sokol +9 other references |
Middle East | |
| Gross (1977) | |
Russia | |
| Galuskin et al. (2012) +1 other reference |
| Galuskina et al. (2015) |
| Galuskin +10 other references | |
| Koneva et al. (1991) | |
Slovakia | |
| Zajzon N. et al. (2021) |
South Africa | |
| Parry et al. (1932) +1 other reference |
| Parry et al. (1932) |
| Parry et al. (1932) +1 other reference | |
| Pohl et al. (1991) |
| Lapis (2004) +1 other reference | |
| Pohl et al. (1991) | |
USA | |
| Murdoch (1954) +6 other references |
| Dunn (1995) |
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N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa