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Kolbeckite
A valid IMA mineral species - grandfathered
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About Kolbeckite
Friedrich L. W. Kolbeck
Formula:
ScPO4 · 2H2O
Colour:
Colourless, light yellow; when impure: cyan-blue, blue-gray, apple-green
Lustre:
Vitreous, Pearly
Hardness:
3 - 5
Specific Gravity:
2.36
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Dr. Friedrich Ludwig Wilhelm Kolbeck (12 January 1860, Dresden - 6 February 1943, Freiberg), German mineralogist, Mining Academy, Freiberg, Germany.
Metavariscite Group. The P analogue of bonacinaite.
A very rare secondary mineral in phosphate deposits and some hydrothermal veins.
A very rare secondary mineral in phosphate deposits and some hydrothermal veins.
Unique Identifiers
Mindat ID:
2239
Long-form identifier:
mindat:1:1:2239:8
Similar Names
| Kolbeckine | A synonym of Herzenbergite |
IMA Classification of Kolbeckite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
ScPO4·2H2O
Classification of Kolbeckite
8.CD.05
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
D : With only medium-sized cations, RO4:H2O = 1:2
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
D : With only medium-sized cations, RO4:H2O = 1:2
40.4.3.3
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
19.9.13
19 : Phosphates
9 : Phosphates of rare earths and Sc
19 : Phosphates
9 : Phosphates of rare earths and Sc
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 |
|---|---|---|
| Kbe | 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 Kolbeckite
Vitreous, Pearly
Transparency:
Transparent
Colour:
Colourless, light yellow; when impure: cyan-blue, blue-gray, apple-green
Hardness:
3 - 5 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
On {010}, distinct, on {100} and {001}, poor.
On {010}, distinct, on {100} and {001}, poor.
Fracture:
Conchoidal
Density:
2.36 g/cm3 (Measured) 2.35 g/cm3 (Calculated)
Optical Data of Kolbeckite
Type:
Biaxial (-)
RI values:
nα = 1.572 - 1.575 nβ = 1.59 nγ = 1.598 - 1.601
2V:
Measured: 60° , Calculated: 74°
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:
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.
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 strong
Pleochroism:
Strong
Comments:
Only in coloured material.
Chemistry of Kolbeckite
Mindat Formula:
ScPO4 · 2H2O
Element Weights:
Elements listed:
Crystallography of Kolbeckite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/c
Setting:
P21/n
Cell Parameters:
a = 5.442 Å, b = 10.2513 Å, c = 8.9094 Å
β = 90.253°
β = 90.253°
Ratio:
a:b:c = 0.531 : 1 : 0.869
Unit Cell V:
497.03 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals commonly short prismatic [001], with prominent {110}, {011}, and less prominent {010}, {101}, and {130}. Platy crystals in radiating aggregates less common.
Twinning:
On {100}, common. May exhibit diagonal sutures on {001}.
Comment:
Pseudo-orthorhombic
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
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
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2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0010338 | Kolbeckite | Yang H, Li C, Jenkins R A, Downs R T, Costin G (2007) Kolbeckite, ScPO4*2H2O, isomorphous with metavariscite Acta Crystallographica C63 i91-i92 |  | 2007 | Hot Springs County, Arkansas, USA | 0 | 293 |
| 0012220 | Kolbeckite | Bull I, Young V, Teat S J, Peng L, Grey C P, Parise J B (2003) Hydrothermal synthesis and structural characterization of four scandium phosphate frameworks Chemistry of Materials 15 3818-3825 | 2003 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.78 Å | (100) |
| 4.44 Å | (100) |
| 2.878 Å | (70) |
| 2.614 Å | (60) |
| 2.849 Å | (50) |
| 3.708 Å | (40) |
| 5.1 Å | (30) |
Comments:
Schlarbaum quarry, Austria. ICDD 38–431.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Geological Setting:
Phosphate deposits; some hydrothermal metallic veins.
Type Occurrence of Kolbeckite
Place of Conservation of Type Material:
Mining Academy, Freiberg, Germany: #50268. U.S. National Museum of Natural History, Washington, D.C., USA: #10632.
Associated Minerals at Type Locality:
Schlarbaum quarry, Klausen, Bad Gleichenberg, Südoststeiermark District, Styria, Austria