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Rappoldite
A valid IMA mineral species
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About Rappoldite
Formula:
PbCo2(AsO4)2 · 2H2O
Colour:
Light brown to brown-red
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
5.28 (Calculated)
Crystal System:
Triclinic
Member of:
Name:
For its discovery locality
Unique Identifiers
Mindat ID:
7044
Long-form identifier:
mindat:1:1:7044:3
IMA Classification of Rappoldite
Approved
IMA Formula:
Pb2+Co2+2(As5+O4)2·2H2O
Approval year:
1998
First published:
2000
Classification of Rappoldite
8.CG.20
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 1:1
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 |
|---|---|---|
| Rap | 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 Rappoldite
Vitreous
Transparency:
Transparent
Colour:
Light brown to brown-red
Streak:
Pale brown-yellow
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
5.28 g/cm3 (Calculated)
Optical Data of Rappoldite
Type:
Biaxial (+)
RI values:
nα = 1.85 nβ = 1.87(2) nγ = 1.90(2)
2V:
Measured: 85° (5), Calculated: 80°
Max. Birefringence:
δ = 0.050
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 distinct
Optical Extinction:
X ~ || c; Y ~ || [120].
Chemistry of Rappoldite
Mindat Formula:
PbCo2(AsO4)2 · 2H2O
Element Weights:
Crystallography of Rappoldite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 11.190(2) Å, b = 10.548(2) Å, c = 7.593(1) Å
α = 100.38(1)°, β = 109.59(2)°, γ = 98.96(1)°
α = 100.38(1)°, β = 109.59(2)°, γ = 98.96(1)°
Ratio:
a:b:c = 1.061 : 1 : 0.72
Unit Cell V:
807.61 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Type material: prismatic or tabular, showing forms {210} and {001}.
Twinning:
By reflection on {230}.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Display Options
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View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
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Labels
Console Off | On | Grey | Yellow
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0014555 | Rappoldite | Effenberger H, Krause W, Bernhardt H J, Martin M (2000) On the symmetry of tsumcorite group minerals based on the new species rappoldite and zincgartrellite Mineralogical Magazine 64 1109-1126 |  | 2000 | Rappold mine, near Schneeberg, Saxony, Germany | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.256 Å | (100) |
| 4.670 Å | (97) |
| 3.072 Å | (56) |
| 2.568 Å | (46) |
| 2.890 Å | (40) |
| 1.731 Å | (38) |
| 2.760 Å | (37) |
Reference:
Comments:
Rappold Mine, Germany. 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] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Rappoldite
General Appearance of Type Material:
Rosette-like aggregates of prismatic to tabular crystals to 2 mm.
Place of Conservation of Type Material:
Bergakademie, Freiberg, Germany, number 79924 (holotype).
Geological Setting of Type Material:
Found on dumps.
Associated Minerals at Type Locality:
Synonyms of Rappoldite
Other Language Names for Rappoldite
Relationship of Rappoldite to other Species
Member of:
Other Members of Tsumcorite Group:
| Alumolukrahnite | Ca[CuAl](AsO4)2(H2O,OH)2 | Tric. 1 : P1 |
| Cabalzarite | CaMg2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Cobaltlotharmeyerite | CaCo2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Cobalttsumcorite | PbCo2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Ferrilotharmeyerite | CaZnFe3+(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Gartrellite | PbCuFe3+(AsO4)2(OH) · H2O | Tric. 1 : P1 |
| Helmutwinklerite | PbZn2(AsO4)2 · 2H2O | Tric. 1 : P1 |
| Kaliochalcite | KCu2(SO4)2[(OH)(H2O)] | Mon. 2/m : B2/m |
| Krettnichite | PbMn3+2(VO4)2(OH)2 | Mon. 2/m : B2/m |
| Lotharmeyerite | CaZn2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Lukrahnite | CaCuFe3+(AsO4)2(OH,H2O)2 | Tric. 1 : P1 |
| Manganlotharmeyerite | CaMn3+2(AsO4)2(OH)2 | Mon. 2/m : B2/m |
| Mawbyite | PbFe3+2(AsO4)2(OH)2 | Mon. 2/m : B2/m |
| Mounanaite | PbFe3+2(VO4)2(OH)2 | Mon. 2/m : B2/m |
| Natrochalcite | NaCu2(SO4)2(OH) · 2H2O | Mon. 2/m : B2/m |
| Nickellotharmeyerite | CaNi2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Nickelschneebergite | BiNi2(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Nickeltsumcorite | Pb(Ni,Fe3+)2(AsO4)2(H2O,OH)2 | Mon. 2/m : B2/m |
| Phosphogartrellite | PbCuFe3+(PO4)2(OH,H2O)2 | Tric. 1 : P1 |
| Schneebergite | BiCo2(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Thometzekite | PbCu2+2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Tsumcorite | PbZn2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Yancowinnaite | PbCuAl(AsO4)2OH · H2O | Tric. 1 : P1 |
| Zincgartrellite | PbZn2(AsO4)2(H2O,OH)2 | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
| 1 photo of Rappoldite associated with Cobaltaustinite | CaCo(AsO4)(OH) |
Related Minerals - Strunz-mindat Grouping
| 8.CG. | Fluckite | CaMn2+(AsO3OH)2 · 2H2O |
| 8.CG. | Dondoellite | Ca2Fe(PO4)2 · 2H2O |
| 8.CG. | 'Ca-Huréaulite' | CaMn5(PO4)4 · 4H2O |
| 8.CG. | Alumolukrahnite | Ca[CuAl](AsO4)2(H2O,OH)2 |
| 8.CG.05 | Parabrandtite | Ca2Mn2+(AsO4)2 · 2H2O |
| 8.CG.05 | Talmessite | Ca2Mg(AsO4)2 · 2H2O |
| 8.CG.05 | Collinsite | Ca2Mg(PO4)2 · 2H2O |
| 8.CG.05 | Messelite | Ca2Fe2+(PO4)2 · 2H2O |
| 8.CG.05 | Gaitite | Ca2Zn(AsO4)2 · 2H2O |
| 8.CG.05 | Anorthoroselite | Ca2Co(AsO4)2 · 2H2O |
| 8.CG.05 | Cassidyite | Ca2Ni(PO4)2 · 2H2O |
| 8.CG.05 | Fairfieldite | Ca2Mn2+(PO4)2 · 2H2O |
| 8.CG.05 | Hillite | Ca2Zn(PO4)2 · 2H2O |
| 8.CG.05 | 'Unnamed (Fe2+-analogue of Parabrandtite)' | Ca2Fe2+(AsO4)2 · 2H2O |
| 8.CG.10 | Zincroselite | Ca2Zn(AsO4)2 · 2H2O |
| 8.CG.10 |
Rappold Mine, Neustädtel, Schneeberg, Erzgebirgskreis, Saxony, Germany