Petterdite
A valid IMA mineral species
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About Petterdite
William Frederick Petterd
Formula:
PbCr3+2(CO3)2(OH)4 · H2O
Colour:
Pale to deep lilac, pinkish violet, pale gray
Lustre:
Pearly, Earthy
Hardness:
2
Specific Gravity:
3.947 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
The name petterdite was first used by Twelvetrees for a mineral that was later shown to be a P-bearing mimetite, and hence discredited (see Petterdite (of Twelvetrees).
This mineral was named by W.D. Birch, U. Kolitsch, T. Witzke, L. Nasdala, and R.S. Bottrill in 2000 in honor of William Frederick Petterd (13 July 1849, Hobart Town, Tasmania, Australia - 15 April 1910, Launceston, Tasmania, Australia), boot importer and scientist. He published many papers on conchology and geology and wrote the Catalogue of the Minerals of Tasmania. He also described dundasite, the Al analogue of this mineral.
This mineral was named by W.D. Birch, U. Kolitsch, T. Witzke, L. Nasdala, and R.S. Bottrill in 2000 in honor of William Frederick Petterd (13 July 1849, Hobart Town, Tasmania, Australia - 15 April 1910, Launceston, Tasmania, Australia), boot importer and scientist. He published many papers on conchology and geology and wrote the Catalogue of the Minerals of Tasmania. He also described dundasite, the Al analogue of this mineral.
Unique Identifiers
Mindat ID:
7099
Long-form identifier:
mindat:1:1:7099:3
Similar Names
| Petterdite (of Twelvetrees) | A synonym of Mimetite |
IMA Classification of Petterdite
Approved
IMA Formula:
Pb2+Cr3+2(CO3)2(OH)4·H2O
Approval year:
1999
First published:
2000
Type description reference:
Classification of Petterdite
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 |
|---|---|---|
| Pte | 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 Petterdite
Pearly, Earthy
Transparency:
Translucent
Colour:
Pale to deep lilac, pinkish violet, pale gray
Streak:
Violet, pale
Hardness:
2 on Mohs scale
Comment:
Estimated
Cleavage:
Imperfect/Fair
Fair parallel to {100} also possibly {010}
Fair parallel to {100} also possibly {010}
Parting:
No parting.
Comment:
"Fracture and tenacity could not be observed."
Density:
3.947 g/cm3 (Calculated)
Optical Data of Petterdite
Type:
Biaxial (-)
RI values:
nα = 1.704(5) nβ = 1.802 nγ = 1.842(5)
2V:
Calculated: 62°
Max. Birefringence:
δ = 0.138
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.
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
Optical Extinction:
X = a; Y = b; Z = c.
Pleochroism:
Visible
Comments:
X = Y = colorless to pale grayish pink; Z = grayish pink.
Comments:
Absorption: X < Z.
Chemistry of Petterdite
Mindat Formula:
PbCr3+2(CO3)2(OH)4 · H2O
Element Weights:
Crystallography of Petterdite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 9.079(3) Å, b = 16.321(9) Å, c = 5.786(7) Å
Ratio:
a:b:c = 0.556 : 1 : 0.355
Unit Cell V:
857.36 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals are poorly developed, flattened on {010}, and slightly elongate along [001] or, less commonly, [100]. Terminations, in the direction of [001], typically have a frayed appearance.
Twinning:
No twinning.
Comment:
Space Group: [P bnm] (by analogy to dundasite).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.937 Å | (100) |
| 3.633 Å | (70) |
| 4.686 Å | (50b) |
| 3.270 Å | (40) |
| 2.718 Å | (40) |
| 2.690 Å | (40) |
| 6.091 Å | (30) |
Comments:
Red Lead Mine, Tasmania, Australia. Data from the type description.
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] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Petterdite
General Appearance of Type Material:
Earthy, pale purplish mineral in crocoite-bearing gossan.
Place of Conservation of Type Material:
Museum Victoria, Melbourne, Australia, M38601.
Associated Minerals at Type Locality:
Synonyms of Petterdite
Other Language Names for Petterdite
Relationship of Petterdite 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 |
| Kochsándorite | CaAl2(CO3)2(OH)4 · H2O | Orth. mmm(2/m2/m2/m) : Pnma |
| 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:
| 19 photos of Petterdite associated with Crocoite | PbCr6+O4 |
| 5 photos of Petterdite associated with Philipsbornite | PbAl3(AsO4)(AsO3OH)(OH)6 |
| 4 photos of Petterdite associated with Cerussite | PbCO3 |
| 3 photos of Petterdite associated with Anglesite | PbSO4 |
| 2 photos of Petterdite associated with Grimaldiite | CrO(OH) |
| 1 photo of Petterdite associated with 'Chrome-Cerussite' | PbCO3 |
| 1 photo of Petterdite associated with Galena | PbS |
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 | Kochsándorite | CaAl2(CO3)2(OH)4 · H2O |
| 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 | 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 Petterdite
Not fluorescent.
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 Petterdite
mindat.org URL:
https://www.mindat.org/min-7099.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 Petterdite
Reference List:
Localities for Petterdite
Showing 2 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 (TL) | |
| Birch et al. (2000) +1 other reference |
Germany | |
| Birch et al. (2000) |
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Red Lead Mine, Dundas mineral field, Zeehan mining district, West Coast municipality, Tasmania, Australia