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Pertoldite
A valid IMA mineral species
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Zemřel prof. RNDr. Zdeněk Pertold, CSc.
Formula:
GeO2
Colour:
White to brownish
Lustre:
Silky
Specific Gravity:
4.30 (Calculated)
Crystal System:
Trigonal
Name:
Named in honor of Dr. Zdeněk Pertold, CSc (December 22, 1933, Prague, Czechia – October 25, 2020), the professor of economic geology in the Department of Geochemistry, Mineralogy and Mineral Resources of the Faculty of Sciences of the Charles University in Prague.
Type Locality:
Dimorph of:
Isostructural with:
The true Ge analogue of quartz.
Unique Identifiers
Mindat ID:
55693
Long-form identifier:
mindat:1:1:55693:0
IMA Classification of Pertoldite
Approved
First published:
2021
Classification of Pertoldite
4.DE.
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
E : With medium-sized cations; with various polyhedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
E : With medium-sized cations; with various polyhedra
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 |
|---|---|---|
| Pert | 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 Pertoldite
Silky
Transparency:
Translucent
Colour:
White to brownish
Streak:
White
Cleavage:
None Observed
Parting:
none
Density:
4.30 g/cm3 (Calculated)
Comment:
4.18 g/cm3 was calculated based on the empirical formula and 4.30 g/cm3 based on the ideal formula.
Optical Data of Pertoldite
Type:
Uniaxial (+)
RI values:
nω = 1.6510 nε = 1.6771
Max. Birefringence:
δ = 0.026
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Optical Extinction:
Parallel extinction. [Not yet published]
Pleochroism:
Non-pleochroic
Comments:
Anisotropic and forms thin (~1 µm) distorted needles or fibers with an average refraction index n = 1.670(5).
The R.I. values used to derive the birefringence were measured on synthetic material (Lignie et al., 2014)
The R.I. values used to derive the birefringence were measured on synthetic material (Lignie et al., 2014)
Chemistry of Pertoldite
Mindat Formula:
GeO2
Elements listed:
Crystallography of Pertoldite
Crystal System:
Trigonal
Class (H-M):
32 - Trapezohedral
Cell Parameters:
a = 4.980(5) Å, c = 5.644(4) Å
Ratio:
a:c = 1 : 1.133
Unit Cell V:
121.22 ų (Calculated from Unit Cell)
Z:
3
Comment:
Space group is P3121 or P3221
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.315 Å | (44) |
| 3.425 Å | (100) |
| 2.490 Å | (31) |
| 2.360 Å | (41) |
| 2.278 Å | (29) |
| 1.867 Å | (31) |
| 1.418 Å | (31) |
| 1.412 Å | (37) |
Type Occurrence of Pertoldite
General Appearance of Type Material:
Aggregates resembling cotton tufts, up to 1 mm in size, composed of acicular crystals up to ~1 μm thick and up to 1 mm in length. Individual crystals are distorted, resembling textile fibers.
Place of Conservation of Type Material:
Collections of the Department of Mineralogy and Petrology, National Museum in Prague, Cirkusová 1740, 19300 Praha 9, Czech Republic, catalogue number P1P 31/2021.
Geological Setting of Type Material:
Formed by direct crystallization from hot (400–500 °C) gasses containing Cl and F as transporting agents at a depth of 40–60 cm under the surface of a burning coal mine dump.
Associated Minerals at Type Locality:
Other Language Names for Pertoldite
Dutch:Pertoldiet
German:Pertoldit
Related Minerals - Strunz-mindat Grouping
| 4.DE. | Colchesterite | Bi3+2Mo6+2O9 |
| 4.DE. | Ziroite | ZrO2 |
| 4.DE.05 | Downeyite | SeO2 |
| 4.DE.10 | Koragoite | (Mn2+,Fe3+)3(Nb,Ta,Ti)2(Nb,Mn)2(W,Ta)2O20 |
| 4.DE.15 | Russellite | Bi2WO6 |
| 4.DE.15 | Koechlinite | Bi2MoO6 |
| 4.DE.15 | Tungstibite | Sb3+2WO6 |
| 4.DE.20 | Tellurite | TeO2 |
| 4.DE.25 | Paratellurite | TeO2 |
| 4.DE.30 | Bismutotantalite | BiTaO4 |
| 4.DE.30 | Stibiotantalite | Sb3+TaO4 |
| 4.DE.30 | Cervantite | Sb3+Sb5+O4 |
| 4.DE.30 | Bismutocolumbite | BiNbO4 |
| 4.DE.30 | Stibiocolumbite | SbNbO4 |
| 4.DE.30 | Clinocervantite | Sb3+Sb5+O4 |
| 4.DE.35 | Baddeleyite | ZrO2 |
| 4.DE.40 | Billwiseite | Sb3+5Nb3WO18 |
| 4.DE.45 | Kyawthuite | Bi3+Sb5+O4 |
Fluorescence of Pertoldite
Not fluorescent.
Other Information
Thermal Behaviour:
Melting point 1116 °C.
Notes:
Slightly soluble in water (0.45 g/100 ml at 25 °C), soluble in HCl, HF and NaOH.
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 Pertoldite
mindat.org URL:
https://www.mindat.org/min-55693.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 Pertoldite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2022) Newsletter 64. Mineralogical Magazine, 86 (1) 178-182 doi:10.1180/mgm.2021.93
Localities for Pertoldite
Showing 1 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 (TL) | |
| Miyawaki et al. (2021) +2 other references |