Chaidamuite
A valid IMA mineral species
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About Chaidamuite
Qaidam (Chaidamu) Basin, China
Formula:
ZnFe3+(SO4)2(OH) · 4H2O
Colour:
Brown to yellowish-brown
Lustre:
Vitreous
Hardness:
2½ - 3
Specific Gravity:
2.722
Crystal System:
Triclinic
Name:
Named for the Qaidam (or Chaidamu) Basin, China. It is a hyperarid basin about 560 km by 160 km that includes saline lakes, marshes, playas and desert. It is located in the Northern Tibetan Plateau, the basin has an elevation of around 3,000 m between two branches of the Kunlun Mountains. Resources include salt, oil, iron ore, and coal. The chaidamuite type locality is on the eastern edge of the basin.
Unique Identifiers
Mindat ID:
958
Long-form identifier:
mindat:1:1:958:4
IMA Classification of Chaidamuite
Approved
IMA Formula:
Zn2+Fe3+(S6+O4)2(OH)·4H2O
Approval year:
1985
First published:
1986
Classification of Chaidamuite
7.DC.30
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
C : With only medium-sized cations; chains of edge-sharing octahedra
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
C : With only medium-sized cations; chains of edge-sharing octahedra
31.9.7.2
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
9 : (AB)(XO4)Zq·xH2O
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
9 : (AB)(XO4)Zq·xH2O
25.5.12
25 : Sulphates
5 : Sulphates of Zn and Hg
25 : Sulphates
5 : Sulphates of Zn and Hg
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 |
|---|---|---|
| Cdm | 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 Chaidamuite
Vitreous
Transparency:
Translucent
Colour:
Brown to yellowish-brown
Streak:
Pale yellow
Hardness:
2½ - 3 on Mohs scale
Cleavage:
Perfect
(100) (001)
(100) (001)
Fracture:
Conchoidal
Density:
2.722(2) g/cm3 (Measured) 2.72 g/cm3 (Calculated)
Optical Data of Chaidamuite
Type:
Biaxial (+)
RI values:
nα = 1.632 nβ = 1.64 nγ = 1.688
2V:
Measured: 44° , Calculated: 46°
Max. Birefringence:
δ = 0.056
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
Dispersion:
strong r < v
Pleochroism:
Strong
Comments:
X= pale yellow, colorless
Y= pale yellow
z= Brownish yellow
Y= pale yellow
z= Brownish yellow
Chemistry of Chaidamuite
Mindat Formula:
ZnFe3+(SO4)2(OH) · 4H2O
Element Weights:
Crystallography of Chaidamuite
Crystal System:
Triclinic
Class (H-M):
1 - Pedial
Space Group:
P1
Cell Parameters:
a = 7.309(2) Å, b = 7.202(2) Å, c = 9.691(3) Å
α = 89.64(3)°, β = 105.89(1)°, γ = 91.11(1)°
α = 89.64(3)°, β = 105.89(1)°, γ = 91.11(1)°
Ratio:
a:b:c = 1.015 : 1 : 1.346
Unit Cell V:
490.54 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Thick tabular to pseudocubic crystals, grains and granular aggregates.
Crystals are thick tabular [001], short prismatic [001], or pseudocubic. Main forms are {001}, {010}, and {101}.
Crystals are thick tabular [001], short prismatic [001], or pseudocubic. Main forms are {001}, {010}, and {101}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.118 Å | (100) |
| 3.090 Å | (95) |
| 9.40 Å | (80) |
| 5.00 Å | (80) |
| 3.64 Å | (70) |
| 5.03 Å | (65) |
| 2.048 Å | (40) |
| 3.57 Å | (35) |
| 2.366 Å | (23) |
| 2.228 Å | (22) |
| 2.850 Å | (20) |
Comments:
Xitieshan mine, China. 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] | |
| 47b : [Sulfates and sulfites] |
Type Occurrence of Chaidamuite
General Appearance of Type Material:
Disseminated fine grains and granular aggregates in which crystals are < 1 mm in maximum dimension.
Place of Conservation of Type Material:
Geology and Mineralogy Resources Museum of Ministry of Geology, Beijing, China.
Geological Setting of Type Material:
Oxidized zone of galena-sphalerite-pyrite deposit.
Associated Minerals at Type Locality:
Synonyms of Chaidamuite
Other Language Names for Chaidamuite
Common Associates
Associations Based on Photo Data:
| 2 photos of Chaidamuite associated with Gypsum | CaSO4 · 2H2O |
| 2 photos of Chaidamuite associated with 'Limonite' |
Related Minerals - Strunz-mindat Grouping
| 7.DC.05 | Meta-aluminite | Al2(SO4)(OH)4 · 5H2O |
| 7.DC.05 | Aluminite | Al2(SO4)(OH)4 · 7H2O |
| 7.DC.10 | Parabutlerite | Fe3+(SO4)(OH) · 2H2O |
| 7.DC.10 | Butlerite | Fe3+(SO4)(OH) · 2H2O |
| 7.DC.15 | Fibroferrite | Fe3+(SO4)(OH) · 5H2O |
| 7.DC.20 | Xitieshanite | Fe3+(SO4)Cl · 6H2O |
| 7.DC.25 | Zincobotryogen | (Zn,Mg,Mn2+)Fe3+(SO4)2(OH) · 7H2O |
| 7.DC.25 | Botryogen | MgFe3+(SO4)2(OH) · 7H2O |
| 7.DC.30 | Guildite | CuFe3+(SO4)2(OH) · 4H2O |
| 7.DC.40 | Pauladamsite | Cu4(SeO3)(SO4)(OH)4 · 2H2O |
| 7.DC.45 | Riotintoite | Al(SO4)(OH) · 3H2O |
| 7.DC.50 | Thorneite | Pb6(Te6+2O10)(CO3)Cl2(H2O) |
| 7.DC.55 | Vendidaite | Al2(SO4)(OH)3Cl · 6H2O |
Fluorescence of Chaidamuite
Not fluorescent.
Other Information
Notes:
Stable in air and insoluble in water, slightly soluble in dilute HCl.
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 Chaidamuite
mindat.org URL:
https://www.mindat.org/min-958.html
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References for Chaidamuite
Localities for Chaidamuite
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.
China (TL) | |
| Li +2 other references |
USA | |
| Castor et al. (2004) |
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Getchell Mine, Adam Peak, Potosi Mining District, Osgood Mountains, Humboldt County, Nevada, USA