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Chambersite
A valid IMA mineral species
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About Chambersite
Formula:
Mn2+3(B7O13)Cl
Colour:
Colorless to deep purple
Lustre:
Vitreous
Hardness:
7
Specific Gravity:
3.49
Crystal System:
Orthorhombic
Member of:
Name:
From Chambers County, Texas, USA, where it was first discovered.
Boracite Group. The manganese analogue of Boracite and Ericaite.
Visit gemdat.org for gemological information about Chambersite.
Visit gemdat.org for gemological information about Chambersite.Unique Identifiers
Mindat ID:
966
Long-form identifier:
mindat:1:1:966:3
IMA Classification of Chambersite
Approved
IMA Formula:
Mn2+3B7O13Cl
First published:
1962
Classification of Chambersite
6.GA.05
6 : BORATES
G : Heptaborates and other megaborates
A : Tekto-heptaborates
6 : BORATES
G : Heptaborates and other megaborates
A : Tekto-heptaborates
25.6.1.3
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
10.1.18
10 : Borates with other anions
1 : Borates with halide
10 : Borates with other anions
1 : Borates with halide
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 |
|---|---|---|
| Cbs | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Chambersite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Chambersite
Vitreous
Transparency:
Transparent, Opaque
Colour:
Colorless to deep purple
Comment:
Darkens with exposure to sunlight
Hardness:
7 on Mohs scale
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.49(2) g/cm3 (Measured) 3.48 g/cm3 (Calculated)
Optical Data of Chambersite
Type:
Biaxial (+)
RI values:
nα = 1.732 nβ = 1.737 nγ = 1.744
2V:
Measured: 83° , Calculated: 82°
Max. Birefringence:
δ = 0.012
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
Chemistry of Chambersite
Mindat Formula:
Mn2+3(B7O13)Cl
Element Weights:
Elements listed:
Crystallography of Chambersite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pca21
Cell Parameters:
a = 8.68(1) Å, b = 8.68(1) Å, c = 12.26(1) Å
Ratio:
a:b:c = 1 : 1 : 1.412
Unit Cell V:
923.70 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Pseudotetrahedral
Twinning:
Rare interpenetrant on [111] with twin plane of {111}
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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View
CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0011067 | Chambersite | Kubel F, Crottaz O (1996) Crystal structure of manganese chlorine boracite, Mn3B7O13Cl Zeitschrift fur Kristallographie 211 924-924 |  | 1996 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.07 Å | (100) |
| 2.74 Å | (60) |
| 2.08 Å | (60) |
| 3.54 Å | (50) |
| 2.17 Å | (50) |
| 1.851 Å | (50) |
| 2.50 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Chambersite
General Appearance of Type Material:
Subhedral to euhedral crystals ranging from less than 1 mm to 1.2 cm on an edge. The dominant form is the positive tetrahedron.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, number 107884.
National Museum of Natural History, Washington, D.C., USA, number 115327.
National Museum of Natural History, Washington, D.C., USA, number 115327.
Geological Setting of Type Material:
Saltdome caprock.
Associated Minerals at Type Locality:
Other Language Names for Chambersite
Relationship of Chambersite to other Species
Member of:
Other Members of Boracite Group:
| Boracite | Mg3(B7O13)Cl | Orth. mm2 : Pca21 |
| Congolite | Fe2+3B7O13Cl | Trig. 3m : R3c |
| Ericaite | Fe2+3(B7O13)Cl | Orth. mm2 : Pca21 |
| Trembathite | Mg3B7O13Cl | Trig. 3m : R3c |
Related Minerals - Strunz-mindat Grouping
| 6.GA.05 | Ericaite | Fe2+3(B7O13)Cl |
| 6.GA.05 | Boracite | Mg3(B7O13)Cl |
| 6.GA.10 | Congolite | Fe2+3B7O13Cl |
| 6.GA.10 | Trembathite | Mg3B7O13Cl |
| 6.GA.30 | Korzhinskite | Ca(B2O4) · H2O |
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 Chambersite
mindat.org URL:
https://www.mindat.org/min-966.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 Chambersite
Reference List:
Beck, Russell M. Honea. and.Frank.R. (1962) Chambersite, a new mineral. American Mineralogist, 47 (5-6) 665-671
IMA (1967) International Mineralogical Association: Commission on New Minerals and Mineral Names. Mineralogical Magazine and Journal of the Mineralogical Society, 36 (277) 131-136 doi:10.1180/minmag.1967.036.277.20
Nelmes, R. J. (1974) Structural studies of boracites. A review of the properties of boracites. Journal of Physics C: Solid State Physics, 7 (21) 3840-3854 doi:10.1088/0022-3719/7/21/008
Kubel, F., Crottaz, O. (1996) Crystal structure of manganese chlorine boracite, Mn3B7O13Cl. Zeitschrift für Kristallographie - Crystalline Materials, 211 (12) 924 doi:10.1524/zkri.1996.211.12.924
Fan, Delian; Yang, Peiji; Wang, Rao (1999) Characteristics and origin of the Middle Proterozoic Dongshuichang chambersite deposit, Jixian, Tianjin, China. Ore Geology Reviews, 15 (1-3). p.15-29. doi:10.1016/s0169-1368(99)00012-8
Grice, J. D., Gault, R. A., Van Velthuizen, J. (2005) Borate minerals of the Penobsquis and Millstream deposits, southern New Brunswick, Canada. The Canadian Mineralogist, 43 (5) 1469-1487 doi:10.2113/gscanmin.43.5.1469
Localities for Chambersite
Showing 13 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.
Canada | |
| Grice et al. (2005) |
| Grice (2002) | |
| Fundy Geological Museum specimen |
China | |
| wrgis.wr.usgs.gov (2004) |
| Xiong Song (1989) |
| Xiong Song (1989) |
| Xiong Song (1989) +2 other references |
Madagascar | |
| Laurs et al. (Skip) |
USA | |
| Smith (1994) |
| Smith (1994) |
| Smith (1994) | |
| Beck (1962) |
| Beck (1962) |
Quick NavTopAbout ChambersiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPronunciation Physical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsStrunz-MindatOther InformationInternet Links References Localities Locality List
Barbers Hill Salt Dome, Mont Belvieu, Chambers County, Texas, USA