Alumohydrocalcite
A valid IMA mineral species - grandfathered
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About Alumohydrocalcite
Formula:
CaAl2(CO3)2(OH)4 · 4H2O
Previously assumed to have only three water molecules per formula unit.
Colour:
Chalky white to pale blue, pale yellow, cream, gray; pale rose or brownish pink to dark violet in Cr-bearing varieties
Hardness:
2½
Specific Gravity:
2.21 - 2.24
Crystal System:
Triclinic
Member of:
Name:
In allusion to the composition, containing ALUMinium, water (HYDRated) and a calcium carbonate (CALCITE) component.
Unique Identifiers
Mindat ID:
157
Long-form identifier:
mindat:1:1:157:3
GUID
(UUID V4):
(UUID V4):
63678b6b-53c3-4392-a78e-3751bcc1137f
IMA Classification of Alumohydrocalcite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1926
Classification of Alumohydrocalcite
5.DB.05
5 : CARBONATES (NITRATES)
D : Carbonates with additional anions, with H2O
B : With large and medium-sized cations
5 : CARBONATES (NITRATES)
D : Carbonates with additional anions, with H2O
B : With large and medium-sized cations
16b.2.3.1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
2 : AmBn(XO3)pZqxH2O & with (m+n):p = 3:2
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
2 : AmBn(XO3)pZq
11.7.7
11 : Carbonates
7 : Carbonates of Al
11 : Carbonates
7 : Carbonates of Al
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Ahcal | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Alumohydrocalcite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Alumohydrocalcite
Transparency:
Transparent, Translucent, Opaque
Colour:
Chalky white to pale blue, pale yellow, cream, gray; pale rose or brownish pink to dark violet in Cr-bearing varieties
Comment:
colourless in transmitted light
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
On {100}; on {010} imperfect.
On {100}; on {010} imperfect.
Density:
2.21 - 2.24 g/cm3 (Measured) 2.213 g/cm3 (Calculated)
Optical Data of Alumohydrocalcite
Type:
Biaxial (-)
RI values:
nα = 1.485 - 1.502 nβ = 1.553 - 1.562 nγ = 1.570 - 1.585
2V:
Measured: 64° , Calculated: 50° to 60°
Max Birefringence:
δ = 0.085
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
r > v strong
Optical Extinction:
X = b; Extinction inclined 6°–10°.
Chemistry of Alumohydrocalcite
Mindat Formula:
CaAl2(CO3)2(OH)4 · 4H2O
Previously assumed to have only three water molecules per formula unit.
Previously assumed to have only three water molecules per formula unit.
Common Impurities:
Cr
Crystallography of Alumohydrocalcite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 5.71(5) Å, b = 6.54(4) Å, c = 14.6(2) Å
α = 81.8(3)°, β = 83.9(3)°, γ = 86.5(7)°
α = 81.8(3)°, β = 83.9(3)°, γ = 86.5(7)°
Ratio:
a:b:c = 0.873 : 1 : 2.232
Unit Cell V:
537 ų
Morphology:
As fibers and needles, to 2.5 mm; commonly in radial aggregates and spherulites, feltlike crystal linings, and powdery to chalky masses.
Comment:
Space Group: P1 or P1 (chromian).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.21 Å | (30) |
| 6.50 Å | (70) |
| 6.25 Å | (100) |
| 3.23 Å | (60) |
| 2.860 Å | (30) |
| 2.519 Å | (40) |
| 2.039 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Geological Setting:
Formed at low temperature by the action of carbonated waters on allophane or dickite in dolomites and limestones; chromian varieties are typically formed near altering chromite from serpentinites.
Type Occurrence of Alumohydrocalcite
General Appearance of Type Material:
Finely porous, chalk-like masses.
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 77088.
Geological Setting of Type Material:
Limestone and siliceous rock.
Associated Minerals at Type Locality:
Reference:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A) Bilibine, G. (1926) Alumohydrocalcite - a new species. Zapiski Rossiiskogo Mineralogicheskogo Obshchetstva: 55: 243-258.
Synonyms of Alumohydrocalcite
Other Language Names for Alumohydrocalcite
Varieties of Alumohydrocalcite
| Chromium-bearing Alumohydrocalcite | A chromium-bearing variety of alumohydrocalcite. Cr-dominant samples are grguricite. |
| Knipovichite | Equivalent to Chromian Alumohydrocalcite. Discredited as a distinct species. |
Relationship of Alumohydrocalcite to other Species
Member of:
Other Members of this group:
| Dresserite | BaAl2(CO3)2(OH)4 · H2O | Orth. mmm (2/m 2/m 2/m) |
| Dundasite | PbAl2(CO3)2(OH)4 · H2O | Orth. mmm (2/m 2/m 2/m) |
| Grguricite | CaCr2(CO3)2(OH)4 · 4H2O | Tric. 1 : P1 |
| Hydrodresserite | BaAl2(CO3)2(OH)4 · 3H2O | Tric. 1 : P1 |
| Kochsándorite | CaAl2(CO3)2(OH)4 · H2O | Orth. mmm (2/m 2/m 2/m) : Pnma |
| Petterdite | PbCr3+2(CO3)2(OH)4 · H2O | Orth. mmm (2/m 2/m 2/m) |
| Strontiodresserite | SrAl2(CO3)2(OH)4 · H2O | Orth. mmm (2/m 2/m 2/m) |
| Unnamed (Ca-analogue of Petterdite) | CaCr3+2(CO3)2(OH)4 · H2O |
Common Associates
Associated Minerals Based on Photo Data:
| 11 photos of Alumohydrocalcite associated with Azurite | Cu3(CO3)2(OH)2 |
| 8 photos of Alumohydrocalcite associated with Fluorapatite | Ca5(PO4)3F |
| 8 photos of Alumohydrocalcite associated with Malachite | Cu2(CO3)(OH)2 |
| 4 photos of Alumohydrocalcite associated with Allophane | (Al2O3)(SiO2)1.3-2 · 2.5-3H2O |
| 4 photos of Alumohydrocalcite associated with Calcite | CaCO3 |
| 3 photos of Alumohydrocalcite associated with Carbonatecyanotrichite | Cu4Al2(CO3,SO4)(OH)12 · 2H2O |
| 3 photos of Alumohydrocalcite associated with Siderite | FeCO3 |
| 2 photos of Alumohydrocalcite associated with Clinopyroxene Subgroup | |
| 2 photos of Alumohydrocalcite associated with Dickite | Al2(Si2O5)(OH)4 |
| 2 photos of Alumohydrocalcite associated with Pyrite | FeS2 |
Related Minerals - Strunz-mindat Grouping
| 5.DB. | Grguricite | CaCr2(CO3)2(OH)4 · 4H2O |
| 5.DB.05 | Nasledovite | PbMn3Al4(CO3)4(SO4)O5 · 5H2O |
| 5.DB.05 | Para-alumohydrocalcite | CaAl2(CO3)2(OH)4 · 6H2O |
| 5.DB.05 | UM1977-02-CO:AlCaH | Ca6Al2(CO3)3O6 · 32H2O |
| 5.DB.10 | Dresserite | BaAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Dundasite | PbAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Montroyalite | Sr4Al8(CO3)3(OH,F)26 · 10-11H2O |
| 5.DB.10 | Strontiodresserite | SrAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Petterdite | PbCr3+2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Kochsándorite | CaAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Unnamed (Ca-analogue of Petterdite) | CaCr3+2(CO3)2(OH)4 · H2O |
| 5.DB.15 | Hydrodresserite | BaAl2(CO3)2(OH)4 · 3H2O |
| 5.DB.20 | Schuilingite-(Nd) | PbCu(Nd,Gd,Sm,Y)(CO3)3(OH) · 1.5H2O |
| 5.DB.25 | Sergeevite | Ca2Mg11(CO3)9(HCO3)4(OH)4 · 6H2O |
| 5.DB.30 | Szymańskiite | [H3O]+8[Hg2]2+8(Ni,Mg)6[CO3]12(OH)12 · 3H2O |
| 5.DB.35 | Lusernaite-(Y) | Y4Al(CO3)2(OH)10F · 6H2O |
| 5.DB.40 | Putnisite | SrCa4Cr3+8(CO3)8SO4(OH)16 · 23H2O |
Other Information
Notes:
Readily soluble in acids. Decomposed by boiling water with separation of calcium carbonate and hydrous aluminum oxide.
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 Alumohydrocalcite
mindat.org URL:
https://www.mindat.org/min-157.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 Alumohydrocalcite
Localities for Alumohydrocalcite
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.
Argentina | |
| Hugo A. Peña (1970) |
| Raúl Jorge Tauber Larry´s collection. |
Austria | |
| G. Blass (2003) |
| Walter et al. (2021) |
| Niedermayr et al. (1995) |
| Auer (2020) |
Belgium | |
| Fransolet et al. (1975) +2 other references |
| tw.strahlen.org (n.d.) | |
| Blondieau (2012) |
France | |
| G. Favreau communication et al. (Allier, France) |
| Queneau (n.d.) +1 other reference |
Germany | |
| Schnorrer-Köhler et al. (1990) |
| Kautz (1968) |
| Blass +1 other reference |
| Blass +1 other reference | |
| Blass +1 other reference |
| Blass +1 other reference |
| Hentschel (1987) |
| Hentschel (1993) |
Greece | |
| Rieck et al. (2018) |
Hungary | |
| |
| Sajó et al. (2007) |
Italy | |
| Sabelli C. et al. (GR) |
| "Lithothek der Münchener Micromounter" ... |
| www.comune.pisa.it (2000) |
| Muenchener Micromounter-Lithothek |
| Neschen (n.d.) |
| Orlandi et al. (2009) |
| Orlandi (1999) +1 other reference |
| Orlandi et al. (2009) |
| Daleffe et al. (2012) |
Japan | |
| Hori +1 other reference |
| Mineralogical Society of America - ... |
| Alfredo Petrov specimens |
| The Mineral Species of Japan (5th ed) |
| Ohe Rikosya specimens (Kyoto) |
Kyrgyzstan | |
| Uvarova et al. (2005) +1 other reference |
Pakistan | |
| Mineralogical Society of America - ... |
Poland | |
| Hoehne K. 1953: Ein neues Vorkommen von ... |
| Eligiusz Szełęg private collection +2 other references |
| Wojciech Czapliński |
Russia (TL) | |
| Palache et al. (1951) +1 other reference |
Slovakia | |
| Cílek (1999) |
| Bačo |
| Pauliš |
Spain | |
| Bareche (2005) |
| Mineralogistes de Catalunya (1997) |
Turkmenistan | |
| Evseev (1995) |
UK | |
| Alabaster (1990) |
| Day (1999) |
| Ryback G. "Alumohydrocalcite from ... |
| Mineralogical Society of America - ... |
| Turner R.W. and Rumsey (2007) +1 other reference |
USA | |
| Van Nostrand Reinholt Press: 198. +2 other references |
| Dunning (2000) |
| Castor et al. (2004) |
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Laacher See Volcanic Complex, Germany