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Kochsándorite
A valid IMA mineral species
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About Kochsándorite
Prof. Sándor Koch
Formula:
CaAl2(CO3)2(OH)4 · H2O
Colour:
Colourless
Lustre:
Vitreous, Silky
Hardness:
2 - 2½
Specific Gravity:
2.486
Crystal System:
Orthorhombic
Member of:
Name:
Named after Sándor Koch (16 August 1896, Cluj-Napoca, Romania - 25 May 1983, Szeged, Hungary), former professor of mineralogy, petrography and geochemistry at the University of Szeged, Hungary. He wrote 'The History of Minerals in Hungary' and 'Minerals of Hungary'. He was the coauthor of the descriptions of fülöppite and mátraite.
Type Locality:
Name Encoding
ASCII-7:
Kochsandorite
Unique Identifiers
Mindat ID:
27424
Long-form identifier:
mindat:1:1:27424:9
IMA Classification of Kochsándorite
Classification of Kochsándorite
5.DB.10
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
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 for Standard |
|---|---|---|
| Ksd | 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 Kochsándorite
Vitreous, Silky
Transparency:
Transparent
Comment:
Silky in aggregates.
Colour:
Colourless
Comment:
Larger aggregates are white to pale brown.
Streak:
White
Hardness:
2 - 2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
None observed
Density:
2.486(20) g/cm3 (Measured) 2.514(2) g/cm3 (Calculated)
Optical Data of Kochsándorite
Type:
Biaxial (-)
RI values:
nα = 1.597(3) nγ = 1.603(6)
Max. Birefringence:
δ = 0.006
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.
No measured or calculated 2V is on file for this mineral, so the value used here (90°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (90°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r < v, weak.
Pleochroism:
Non-pleochroic
Comments:
2V could not be measured.
Chemistry of Kochsándorite
Mindat Formula:
CaAl2(CO3)2(OH)4 · H2O
Element Weights:
Crystallography of Kochsándorite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 15.564(6) Å, b = 5.591(4) Å, c = 9.112(4) Å
Ratio:
a:b:c = 2.784 : 1 : 1.63
Unit Cell V:
792.9 ų
Z:
4
Morphology:
Forms, in order of prominence: {100}, {110}, {001} and {010}.
Twinning:
None observed.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.86 Å | (87) |
| 7.78 Å | (62) |
| 5.92 Å | (100) |
| 4.37 Å | (86) |
| 2.957 Å | (48) |
| 2.946 Å | (44) |
| 2.569 Å | (17) |
| 1.902 Å | (26) |
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] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
Type Occurrence of Kochsándorite
General Appearance of Type Material:
Spherical aggregates of acicular crystals up to 0.5 mm long, forming strings in massive coal.
Place of Conservation of Type Material:
Hungarian Natural History Museum, Budapest, Hungary, 568/2004.
Herman Otto Museum, Miskolc, Hungary, 2004.72.
Mineral Museum, Lajos Kövecses-Varga-Siofok, Hungary, 12004/1-3.
Herman Otto Museum, Miskolc, Hungary, 2004.72.
Mineral Museum, Lajos Kövecses-Varga-Siofok, Hungary, 12004/1-3.
Geological Setting of Type Material:
Coal mine.
Associated Minerals at Type Locality:
Synonyms of Kochsándorite
Other Language Names for Kochsándorite
Relationship of Kochsándorite to other Species
Member of:
Other Members of Dresserite Group:
| Alumohydrocalcite | CaAl2(CO3)2(OH)4 · 4H2O | Tric. 1 : P1 |
| Dresserite | BaAl2(CO3)2(OH)4 · H2O | Orth. mmm(2/m2/m2/m) |
| Dundasite | PbAl2(CO3)2(OH)4 · H2O | Orth. mmm(2/m2/m2/m) |
| Grguricite | CaCr2(CO3)2(OH)4 · 4H2O | Tric. 1 : P1 |
| Hydrodresserite | BaAl2(CO3)2(OH)4 · 3H2O | Tric. 1 : P1 |
| Petterdite | PbCr3+2(CO3)2(OH)4 · H2O | Orth. mmm(2/m2/m2/m) |
| Strontiodresserite | SrAl2(CO3)2(OH)4 · H2O | Orth. mmm(2/m2/m2/m) |
| 'Unnamed (Ca-analogue of Petterdite)' | CaCr3+2(CO3)2(OH)4 · H2O |
Common Associates
Associations Based on Photo Data:
| 2 photos of Kochsándorite associated with 'Humic coal series' | |
| 1 photo of Kochsándorite associated with Böhmite | AlO(OH) |
Related Minerals - Strunz-mindat Grouping
| 5.DB. | Rigrahamite | Na2Ca2Th2(CO3)4(HCO3)2(OH)4(H2O)7 |
| 5.DB. | Grguricite | CaCr2(CO3)2(OH)4 · 4H2O |
| 5.DB.05 | Para-alumohydrocalcite | CaAl2(CO3)2(OH)4 · 6H2O |
| 5.DB.05 | Nasledovite | PbMn3Al4(CO3)4(SO4)O5 · 5H2O |
| 5.DB.05 | 'UM1977-02-CO:AlCaH' | Ca6Al2(CO3)3O6 · 32H2O |
| 5.DB.05 | Alumohydrocalcite | CaAl2(CO3)2(OH)4 · 4H2O |
| 5.DB.10 | Dresserite | BaAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Dundasite | PbAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | 'Unnamed (Ca-analogue of Petterdite)' | CaCr3+2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Petterdite | PbCr3+2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Strontiodresserite | SrAl2(CO3)2(OH)4 · H2O |
| 5.DB.10 | Montroyalite | Sr4Al8(CO3)3(OH,F)26 · 10-11H2O |
| 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 |
Fluorescence of Kochsándorite
Pale yellow under both short and long wave UV.
Other Information
IR Spectrum:
The strongest FTIR absorption bands are at 559, 973, 1361, 1445, 1520, 1574, 1652, 3145, 3452 and 3548 cm–1. The FTIR spectrum is very similar to that of dresserite and strontiodresserite.
Notes:
Dissolves quickly in dilute HCl with effervescence.
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 Kochsándorite
mindat.org URL:
https://www.mindat.org/min-27424.html
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Please feel free to link to this page.
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References for Kochsándorite
Localities for Kochsándorite
Showing 3 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.
Greece | |
| Rieck et al. (2018) |
Hungary (TL) | |
| Sajó +1 other reference |
| Geoda/2007/1 +1 other reference |
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Coal Mine, Mány, Bicskei District, Fejér County, Hungary