Cahnite (original) (raw)
A valid IMA mineral species - grandfathered
About CahniteHide
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Formula:
Ca2[B(OH)4](AsO4)
Colour:
Colorless to white, golden brown
Lustre:
Vitreous, Sub-Vitreous, Resinous
Crystal System:
Tetragonal
Name:
Named in 1921 by Charles Palache, but not described until 1927 by Charles Palache and Lawson Henry Bauer in honor of Mr. Lazard Cahn [May 23, 1865 Saint Joseph, Missouri, USA - May 22, 1940 Colorado Springs, Colorado, USA] morphological crystallographer, mineral collector and mineral dealer, who first recognized the material.
Unique IdentifiersHide
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Long-form identifier:
mindat:1:1:851:2
06c3f907-587f-4421-bbb9-824bb0c3f732
IMA Classification of CahniteHide
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Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca2B(AsO4)(OH)4
Type description reference:
Classification of CahniteHide
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6.AC.70
6 : BORATES
A : Monoborates
C : B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc
43.4.4.1
43 : COMPOUND PHOSPHATES, ETC.
4 : Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
10.2.2
10 : Borates with other anions
2 : Borates with phosphate or arsenate
Mineral SymbolsHide
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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference |
|---|---|---|
| Cah | 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 CahniteHide
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Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Sorry, your browser doesn't support HTML5 audio. | Jolyon Ralph | United Kingdom |
Physical Properties of CahniteHide
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Vitreous, Sub-Vitreous, Resinous
Transparency:
Transparent, Translucent
Colour:
Colorless to white, golden brown
Comment:
Colourless in transmitted light.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.156 g/cm3 (Measured) 3.22 g/cm3 (Calculated)
Optical Data of CahniteHide
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RI values:
_n_ω = 1.655 - 1.662 _n_ε = 1.656 - 1.663
δ = 0.001
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Dispersion:
Strong; exhibits anomalous interference colors.
Pleochroism:
Non-pleochroic
Comments:
Exhibits abnormal interference colours that make the mineral easily recognizable under the microscope.
Chemistry of CahniteHide
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Mindat Formula:
Ca2[B(OH)4](AsO4)
Crystallography of CahniteHide
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Crystal System:
Tetragonal
Class (H-M):
4 - Disphenoidal
Cell Parameters:
a = 7.09 Å, c = 6.19 Å
Unit Cell V:
311.16 ų (Calculated from Unit Cell)
Morphology:
Single untwinned crystals rare, pseudo-tetrahedral habit.
Twinning:
Almost universal on {110}, with the individuals interpenetrating symmetrically. When the sphenoid faces are well-developed, the twins have a characteristic cruciform appearance.
Crystal StructureHide
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| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000097 | Cahnite | Prewitt C T, Buerger M J (1961) The crystal structure of cahnite, Ca2BAsO4(OH)4 American Mineralogist 46 1077-1085 |  |
1961 | Franklin, New Jersey, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder DiffractionHide
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Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.02 Å | (20) |
| 4.67 Å | (20) |
| 3.56 Å | (100) |
| 2.833 Å | (19) |
| 2.640 Å | (48) |
| 2.336 Å | (17) |
| 1.818 Å | (52) |
Geological EnvironmentHide
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Geological Setting:
cavities in boron-bearing and arsenate-bearing vugs in basalt, boron-bearing and arsenate-bearing hydrothermal veins
Type Occurrence of CahniteHide
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General Appearance of Type Material:
Tiny white glassy crystals, characteristically twinned with generally etched crystal faces.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, numbers 90010, 90015, 90016, 90019.
National Museum of Natural History, Washington, D.C., USA, number 95568.
Geological Setting of Type Material:
Cavities in manganaxinite veinlets traversing Precambrian metamorphosed Zn-Mn-Fe orebody.
Associated Minerals at Type Locality:
Reference:
Palache, C., Bauer, L.H. (1927) Cahnite, a new boro-arsenate of calcium from Franklin, New Jersey. American Mineralogist: 12: 149-153.
Synonyms of CahniteHide
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Other Language Names for CahniteHide
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Common AssociatesHide
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Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat GroupingHide
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| 6.AC.05 | Sinhalite | MgAl(BO4) | Orth. m m m _(_2/_m_2/_m_2/m ) |
|---|---|---|---|
| 6.AC.10 | Pseudosinhalite | Mg2Al3(BO3)2(OH)O3 | Mon. 2/m : _P_21/b |
| 6.AC.15 | Béhierite | (Ta5+,Nb5+)(BO4) | Tet. 4/m m m _(_4/_m_2/_m_2/m ) : _I_41/a m d |
| 6.AC.15 | Schiavinatoite | (Nb,Ta)(BO4) | Tet. 4/m m m _(_4/_m_2/_m_2/m ) : _I_41/a m d |
| 6.AC.20 | Frolovite | Ca[B(OH)4]2 | Tric. 1 : _P_1 |
| 6.AC.25 | Hexahydroborite | Ca[B(OH)4]2 · 2H2O or CaB2O4 · 6H2O | Mon. 2/m : _B_2/b |
| 6.AC.30 | Henmilite | Ca2Cu[B(OH)4]2(OH)4 | Tric. 1 : _P_1 |
| 6.AC.35 | Bandylite | Cu[B(OH)4]Cl | Tet. 4/m m m _(_4/_m_2/_m_2/m ) : _P_4/n m m |
| 6.AC.40 | Teepleite | Na2[B(OH)4]Cl | Tet. 4/m m m _(_4/_m_2/_m_2/m ) : _P_4/n m m |
| 6.AC.45 | Moydite-(Y) | Y[B(OH)4](CO3) | Orth. m m m _(_2/_m_2/_m_2/m ) : P b c a |
| 6.AC.50 | Carboborite | Ca2Mg[B(OH)4]2(CO3)2 · 4H2O | Mon. 2/m |
| 6.AC.55 | Sulfoborite | Mg3[B(OH)4]2(SO4)(OH,F)2 | Orth. m m m _(_2/_m_2/_m_2/m ) : P n m a |
| 6.AC.60 | Lüneburgite | Mg3[B2(OH)6](PO4)2 · 6H2O | Tric. 1 : _P_1 |
| 6.AC.65 | Seamanite | Mn2+3[B(OH)4](PO4)(OH)2 | Orth. m m m _(_2/_m_2/_m_2/m ) |
Fluorescence of CahniteHide
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Fluoresces moderate creamy white in SW UV (Franklin).
Other InformationHide
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Notes:
Readily soluble in dilute HCl.
Fuses quietly at about 3 yielding the green flame of boron. In the closed tube, heated alone it yields water and becomes opaque but does not fuse; heated with potassium carbonate and carbon it yields an arsenic mirror.
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 CahniteHide
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References for CahniteHide
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Reference List:
Shiraga, Kanako, Kusachi, Isao, Kobayashi, Shoichi, Takechi, Yasushi (2002) Cahnite from Fuka, Okayama Prefecture, Japan. Journal of Mineralogical and Petrological Sciences, 97 (2) 70-73 doi:10.2465/jmps.97.70
Localities for CahniteHide
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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the 
symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Locality ListHide
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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.