Kratochvílite
A valid IMA mineral species - grandfathered
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About Kratochvílite
Josef Kratochvíl
Formula:
C13H10
Colour:
Colorless
Specific Gravity:
1.206
Crystal System:
Orthorhombic
Name:
To honor Josef Kratochvíl (28 July 1878, Caslav, Czech Republic - 1 November 1958, Prague, Czech Republic), petrographer and professor, Charles University, Prague, Czech Republic. He wrote the eight-volume work, 'The Topographic Mineralogy of Bohemia'.
Organic compound formed in burning pyritic shale or coal fires. It is uncertain whether kratochvíllite is the chemical fluorene (more specifically: 9H-fluorene) (C13H10) or anthracene (C14H10) - further study of type material needed.
Note (04.04.2020): seems like it is fluorene, as "anthracene" is now approved as freitalite.
Both compounds are well-known polycyclic aromatic hydrocarbons (PAHs), and their structural formulas are (CH)4C2(CH2)C2(CH)4 (also known as tricyclo[7.4.0.02,7]trideca-2,4,6,9,11,13-hexaene, that is, two benzene rings fused with a single cyclopentane one) and (CH)4C2(CH)2C2(CH4)4 (also known as tricyclo[8.4.0.03,8]tetradeca-1,3,5,7,9,11,13-heptaene, i.e., three benzene rings fused), respectively.
Note (04.04.2020): seems like it is fluorene, as "anthracene" is now approved as freitalite.
Both compounds are well-known polycyclic aromatic hydrocarbons (PAHs), and their structural formulas are (CH)4C2(CH2)C2(CH)4 (also known as tricyclo[7.4.0.02,7]trideca-2,4,6,9,11,13-hexaene, that is, two benzene rings fused with a single cyclopentane one) and (CH)4C2(CH)2C2(CH4)4 (also known as tricyclo[8.4.0.03,8]tetradeca-1,3,5,7,9,11,13-heptaene, i.e., three benzene rings fused), respectively.
Name Encoding
ASCII-7:
Kratochvilite
Unique Identifiers
Mindat ID:
2269
Long-form identifier:
mindat:1:1:2269:5
IMA Classification of Kratochvílite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1937
Classification of Kratochvílite
10.BA.25
10 : ORGANIC COMPOUNDS
B : Hydrocarbons
A : Hydrocarbons
10 : ORGANIC COMPOUNDS
B : Hydrocarbons
A : Hydrocarbons
50.3.1.1
50 : ORGANIC COMPOUNDS
3 : Hydrocarbons
50 : ORGANIC COMPOUNDS
3 : Hydrocarbons
32.4
32 : Hydrocarbons, Resins and other Organic Compounds
32 : Hydrocarbons, Resins and other Organic Compounds
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 |
|---|---|---|
| Ktc | 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 Kratochvílite
Transparency:
Translucent
Colour:
Colorless
Density:
1.206 g/cm3 (Measured) 1.197 g/cm3 (Calculated)
Optical Data of Kratochvílite
Type:
Biaxial (+)
RI values:
nα = 1.578 nβ = 1.663 nγ = 1.919
Max. Birefringence:
δ = 0.341
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:
Very 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.
No measured or calculated 2V is on file for this mineral, so the value used here (67°) 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 (67°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
very weak
Chemistry of Kratochvílite
Mindat Formula:
C13H10
Elements listed:
Crystallography of Kratochvílite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 8.50 Å, b = 5.71 Å, c = 19.00 Å
Ratio:
a:b:c = 1.489 : 1 : 3.327
Unit Cell V:
922.17 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space Group: P nam.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.68 Å | (100b) |
| 9.39 Å | (70) |
| 4.21 Å | (70b) |
| 3.79 Å | (50) |
| 3.38 Å | (90) |
| 2.54 Å | (60) |
| 2.45 Å | (50) |
Comments:
Data for synthetic C13H10.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Kratochvílite
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
Burning pyritic shale.
Associated Minerals at Type Locality:
Synonyms of Kratochvílite
Other Language Names for Kratochvílite
Common Associates
Associations Based on Photo Data:
| 1 photo of Kratochvílite associated with Native Sulphur | S8 |
Related Minerals - Strunz-mindat Grouping
| 10.BA. | Freitalite | C14H10 |
| 10.BA.05 | Fichtelite | C19H34 |
| 10.BA.10 | Branchite | C20H34 |
| 10.BA.15 | Dinite | C20H36 |
| 10.BA.20 | Idrialite | C22H14 |
| 10.BA.30 | Carpathite | C24H12 |
| 10.BA.35 | Phylloretine | C18H18 |
| 10.BA.40 | Ravatite | C14H10 |
| 10.BA.45 | Simonellite | C19H24 |
| 10.BA.50 | Evenkite | C21H44 |
| 10.BA.55 | Wampenite | C18H16 |
| 10.BA.60 | 'Scharizerite' |
Fluorescence of Kratochvílite
SW UV: Bright blue-violet.
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 Kratochvílite
mindat.org URL:
https://www.mindat.org/min-2269.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Kratochvílite
Reference List:
Brown, G. M., Bortner, M. H. (1954) On the crystal and molecular structure of fluorene. Acta Crystallographica, 7 (1) 139 doi:10.1107/s0365110x54000382
Bree, A., Zwarich, R. (1969) Vibrational Assignment of Fluorene from the Infrared and Raman Spectra. The Journal of Chemical Physics, 51 (3) 912-920 doi:10.1063/1.1672155
Localities for Kratochvílite
Showing 6 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.
Czech Republic | |
| Žáček et al. (1995) |
| - (1938) |
| Žáček et al. (1998) |
| Matýsek et al. (2022) |
Germany | |
| Witzke et al. (2015) |
Poland | |
| Fabiańska et al. (2015) |
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Kladno mine, Libušin, Kladno District, Central Bohemian Region, Czech Republic