Alstonite
A valid IMA mineral species - grandfathered
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About Alstonite
Alston, England
Formula:
BaCa(CO3)2
Colour:
Colourless to snow white, yellow-gray; pale gray, pale cream, pink to pale rose-red
Lustre:
Vitreous
Hardness:
4 - 4½
Specific Gravity:
3.67 - 3.711
Crystal System:
Triclinic
Name:
After the original locality near Alston, England.
Co-Type Localities:
Polymorph of:
A low-temperature hydrothermal mineral.
Sartori (1975) states that alstonite "is probably an ordered member of a family of possible order-disorder structures."
Compare the chemically very similar benstonite.
Sartori (1975) states that alstonite "is probably an ordered member of a family of possible order-disorder structures."
Compare the chemically very similar benstonite.
Unique Identifiers
Mindat ID:
146
Long-form identifier:
mindat:1:1:146:7
Similar Names
| Ralstonite | A synonym of Hydrokenoralstonite |
IMA Classification of Alstonite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Alstonite
5.AB.35
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
B : Alkali-earth (and other M2+) carbonates
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
B : Alkali-earth (and other M2+) carbonates
14.2.5.1
14 : ANHYDROUS NORMAL CARBONATES
2 : AB(XO3)2
14 : ANHYDROUS NORMAL CARBONATES
2 : AB(XO3)2
11.5.4
11 : Carbonates
5 : Carbonates of Sr and Ba
11 : Carbonates
5 : Carbonates of Sr and Ba
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 |
|---|---|---|
| Asn | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Als | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Alstonite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Alstonite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless to snow white, yellow-gray; pale gray, pale cream, pink to pale rose-red
Comment:
may fade on exposure to light; colorless in transmitted light, showing six or twelve domains
Streak:
White
Hardness:
4 - 4½ on Mohs scale
Cleavage:
Imperfect/Fair
On pseudo-orthorhombic {110}, imperfect
On pseudo-orthorhombic {110}, imperfect
Fracture:
Irregular/Uneven
Density:
3.67 - 3.711 g/cm3 (Measured) 3.67 g/cm3 (Calculated)
Optical Data of Alstonite
Type:
Biaxial (-)
RI values:
nα = 1.526 nβ = 1.671 nγ = 1.672
2V:
Measured: 6° , Calculated: 8°
Max. Birefringence:
δ = 0.146
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:
High (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 weak
Chemistry of Alstonite
Mindat Formula:
BaCa(CO3)2
Element Weights:
Elements listed:
Crystallography of Alstonite
Crystal System:
Triclinic
Cell Parameters:
a = 17.38 Å, b = 14.4 Å, c = 6.12 Å
α = 90.35°, β = 90.12°, γ = 120.08°
α = 90.35°, β = 90.12°, γ = 120.08°
Ratio:
a:b:c = 1.207 : 1 : 0.425
Unit Cell V:
1,325.34 ų (Calculated from Unit Cell)
Z:
24
Morphology:
Crystals are pseudo-dihexagonal dipyramids formed by repeated twinning of individuals bounded by {111} and {021}; also as acute dipyramids bounded by {221}. The evident dipyramidal faces are strongly striated horizontally (perpendicular to pseudohexagonal [0001]) and are divided vertically by a medial, slightly reentrant twinning line parallel to the pseudohexagonal [0001].
Twinning:
Common on pseudo-orthorhombic {110} and {301}, forming the pseudohexagonal groups.
Comment:
Point Group: 1 or 1; Space Group: C1 or C1
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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View
CIF File Best | x | y | z | a | b | c
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Rotation
Stop | Start
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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) |
|---|---|---|---|---|---|---|---|
| M12008 | Alstonite | Bindi, L., Roberts, A.C., Biagioni, C. (2020) Alstonite Mineralogical Magazine 84, 699-704, The crystal structure of alstonite, BaCa(CO3)2: an extraordinary example of 'hidden' complex twinning in large single crystals | 2020 | Fallowfield mine, Northumberland, England | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.55 Å | (100) |
| 2.835 Å | (10) |
| 2.507 Å | (35) |
| 2.050 Å | (23) |
| 1.941 Å | (19) |
| 1.846 Å | (15) |
| 1.589 Å | (8) |
Comments:
Powder pattern essentially identical to that of paralstonite.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks |
Geological Setting:
Typically in low-temperature hydrothermal Pb–Zn deposits; rare in carbonatites.
Type Occurrence of Alstonite
Co-Type Localities:
Place of Conservation of Type Material:
Mining Academy, Freiberg, Germany, 15818.
Geological Setting of Type Material:
Low-temperature hydrothermal deposit.
Associated Minerals at Type Locality:
Synonyms of Alstonite
Other Language Names for Alstonite
Common Associates
Associations Based on Photo Data:
| 67 photos of Alstonite associated with Witherite | BaCO3 |
| 54 photos of Alstonite associated with Baryte | BaSO4 |
| 40 photos of Alstonite associated with Calcite | CaCO3 |
| 37 photos of Alstonite associated with Sphalerite | ZnS |
| 22 photos of Alstonite associated with Fluorite | CaF2 |
| 18 photos of Alstonite associated with Galena | PbS |
| 14 photos of Alstonite associated with Benstonite | Ba6Ca6Mg(CO3)13 |
| 13 photos of Alstonite associated with Quartz | SiO2 |
| 13 photos of Alstonite associated with Pyrite | FeS2 |
| 8 photos of Alstonite associated with Strontianite | SrCO3 |
Related Minerals - Strunz-mindat Grouping
| 5.AB.05 | Siderite | FeCO3 |
| 5.AB.05 | Rhodochrosite | MnCO3 |
| 5.AB.05 | Calcite | CaCO3 |
| 5.AB.05 | Smithsonite | ZnCO3 |
| 5.AB.05 | Gaspéite | NiCO3 |
| 5.AB.05 | Spherocobaltite | CoCO3 |
| 5.AB.05 | Magnesite | MgCO3 |
| 5.AB.05 | Otavite | CdCO3 |
| 5.AB.05 va | 'Parakutnohorite' | |
| 5.AB.10 | Dolomite | CaMg(CO3)2 |
| 5.AB.10 | Minrecordite | CaZn(CO3)2 |
| 5.AB.10 | Škáchaite | CaCo(CO3)2 |
| 5.AB.10 | Ankerite | Ca(Fe2+,Mg)(CO3)2 |
| 5.AB.10 | Kutnohorite | CaMn2+(CO3)2 |
| 5.AB.15 | Aragonite | CaCO3 |
| 5.AB.15 | Cerussite | PbCO3 |
| 5.AB.15 | Witherite | BaCO3 |
| 5.AB.15 | Strontianite | SrCO3 |
| 5.AB.20 | Vaterite | CaCO3 |
| 5.AB.25 | Huntite | CaMg3(CO3)4 |
| 5.AB.30 | Norsethite | BaMg(CO3)2 |
| 5.AB.40 | Paralstonite | BaCa(CO3)2 |
| 5.AB.40 | Olekminskite | Sr(Sr,Ca,Ba)(CO3)2 |
| 5.AB.45 | Barytocalcite | BaCa(CO3)2 |
| 5.AB.50 | Carbocernaite | (Ca,Na)(Sr,Ce,Ba)(CO3)2 |
| 5.AB.55 | Benstonite | Ba6Ca6Mg(CO3)13 |
| 5.AB.60 | Juangodoyite | Na2Cu(CO3)2 |
Fluorescence of Alstonite
Weak yellow fluorescence (SW & LW UV).
Other Information
Notes:
Soluble in dilute HCl.
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 Alstonite
mindat.org URL:
https://www.mindat.org/min-146.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Alstonite
Reference List:
Thomson, Thomas (1835) Account of some new Species of Minerals containing Barytes. Records of General Science, 1. 369-375as Bicalcareocarbonate of Barytes
Mallard, Ernest (1895) Sur l'alstonite et la barytocalcite. Bulletin de la Société Française de Minéralogie, 18 (1) 7-12 doi:10.3406/bulmi.1895.2369
Spencer, L. J. (1910) On the occurrence of Alstonite and Ullmannite (a species new to Britain) in a Barytes-Witherite vein at the New Brancepeth Colliery near Durham. Mineralogical Magazine and Journal of the Mineralogical Society, 15 (71) 302-311 doi:10.1180/minmag.1910.015.71.07
Sartori, Franco (1975) New data on alstonite. Lithos, 8 (3) 199-207 doi:10.1016/0024-4937(75)90036-5
Localities for Alstonite
Showing 35 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 | |
| Mineralogical Society of America - ... |
| Sutherland et al. (2004) |
Austria | |
| Kolitsch et al. (2025) |
| Bernhard et al. (2012) |
Brazil | |
| Guarino (2010) |
| COMIN-CHIARAMONTI et al. (2002) |
Canada | |
| Dalsin et al. (2015) |
| Taseko |
China | |
| Zhang Peishan et al. (1996) |
Finland | |
| LEE et al. (2006) |
France | |
| Mineralogical Society of America - ... +1 other reference |
Greenland | |
| Knudsen et al. (2024) |
| Petersen et al. (1993) |
India | |
| Rock et al. (1992) |
| Kent et al. (1998) |
Italy | |
| Zaccaria et al. (2021) |
Namibia | |
| von Bezing (2007) |
Poland | |
| Dziedzic et al. (1983) +15 other references |
Russia | |
| ... |
| Sorokhtina et al. (2008) |
| Ivanyuk et al. (2017) |
| ... +1 other reference |
| Sharygin et al. (2008) |
UK | |
| Spencer (1910) +1 other reference |
| BMS Collection +3 other references |
| Day (1999) | |
| Ford et al. (1993) |
| Philosophical Magazine and Journal of ... +2 other references |
| T.F. Cotterell : "The mineralogy of ... +1 other reference |
| Alabaster (1990) |
| Mineralogical Society of America - ... | |
| M.Wirth collection | |
USA | |
| Tank (1972) | |
| Rocks & Minerals: 63: 214. +2 other references |
| Fahey et al. (1941) |
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Minerva No. 1 Mine, Ozark-Mahoning group, Cave-In-Rock Mining Sub-District, Hardin County, Illinois, USA