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Cahnite

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Formula:
Ca
 
2
[B(OH)
 
4
](AsO
 
4
)
System:TetragonalColour:Colorless to white, also ...
Hardness:3
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 S[rings, Colorado, USA] morphological crystallographer, mineral collector and mineral dealer, who first recognized the material.


Related to Moydite-(Y).

Classification of Cahnite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:5/G.08-30
Strunz 9th edition ID:6.AC.25
Nickel-Strunz 10th (pending) edition ID:6.AC.70

6 : BORATES
A : Monoborates
C : B(O,OH)4, without and with additional anions; 1(T), 1(T)+OH, etc
Dana 8th edition ID:43.4.4.1

43 : COMPOUND PHOSPHATES, ETC.
4 : Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
Hey's CIM Ref.:10.2.2

10 : Borates with other anions
2 : Borates with phosphate or arsenate
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Type Occurrence of Cahnite

Type Locality:Franklin Mine, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA
Year of Discovery:1921
Geological Setting of type material:Cavities in manganaxinite veinlets traversing Precambrian metamorphosed Zn-Mn-Fe orebody.
Associated Minerals at type locality:
WillemiteRhodonitePyrochroiteHedyphaneDatolite
Baryte

Occurrences of Cahnite

Geological Setting:cavities in boron-bearing and arsenate-bearing vugs in basalt, boron-bearing and arsenate-bearing hydrothermal veins

Physical Properties of Cahnite

Lustre:Vitreous, Sub-Vitreous, Resinous
Diaphaneity (Transparency):Transparent, Translucent
Colour:Colorless to white, also golden brown; colourless in transmitted light.
Streak:White
Hardness (Mohs):3
Tenacity:Brittle
Cleavage:Perfect
On {110}
Fracture:Irregular/Uneven, Sub-Conchoidal
Density (measured):3.156 g/cm3
Density (calculated):3.22 g/cm3

Crystallography of Cahnite

Crystal System:Tetragonal
Class (H-M):4 - Disphenoidal
Space Group:P4
Cell Parameters:a = 7.09Å, c = 6.19Å
Ratio:a:c = 1 : 0.873
Unit Cell Volume:V 311.16 ų (Calculated from Unit Cell)
Z:2
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.
X-Ray Powder Diffraction:
d-spacingIntensity
5.02 (20)
4.67 (20)
3.56 (100)
2.833 (19)
2.640 (48)
2.336 (17)
1.818 (52)

Optical Data of Cahnite

Type:Uniaxial (+)
RI values: nω = 1.655 - 1.662 nε = 1.656 - 1.663
Birefringence:0.001
Maximum Birefringence:δ = 0.001

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:Strong.
Pleochroism:Non-pleochroic
Comments:Exhibits abnormal interference colours.

Chemical Properties of Cahnite

Formula:
Ca
 
2
[B(OH)
 
4
](AsO
 
4
)
Simplified for copy/paste:Ca2[B(OH)4](AsO4)
Essential elements:As, B, Ca, H, O
All elements listed in formula:As, B, Ca, H, O

Relationship of Cahnite to other Species

Common Associates:
ApophylliteBorcariteChabazitePhillipsite
Related Minerals - Nickel-Strunz Grouping):

- +
6.AC.05Sinhalite
MgAl(BO
 
4
)
6.AC.10Pseudosinhalite
Mg
 
2
Al
 
3
(BO
 
3
)
 
2
(OH)O
 
3
6.AC.15Behierite
(Ta
5+
 
,Nb
5+
 
)(BO
 
4
)
6.AC.15Schiavinatoite
(Nb,Ta)(BO
 
4
)
6.AC.20Frolovite
Ca[B(OH)
 
4
]
 
2
6.AC.25Hexahydroborite
Ca[B(OH)
 
4
]
 
2
· 6H
 
2
O
6.AC.30Henmilite
Ca
 
2
Cu[B(OH)
 
4
]
 
2
(OH)
 
4
6.AC.35Bandylite
Cu[B(OH)
 
4
]Cl
6.AC.40Teepleite
Na
 
2
[B(OH)
 
4
]Cl
6.AC.45Moydite-(Y)
Y[B(OH)
 
4
](CO
 
3
)
6.AC.50Carboborite
Ca
 
2
Mg[B(OH)
 
4
]
 
2
(CO
 
3
)
 
2
· 4H
 
2
O
6.AC.55Sulfoborite
Mg
 
3
[B(OH)
 
4
]
 
2
(SO
 
4
)(OH,F)
 
2
6.AC.60Lüneburgite
Mg
 
3
[B
 
2
(OH)
 
6
](PO
 
4
)
 
2
· 6H
 
2
O
6.AC.65Seamanite
Mn
2+
3
[B(OH)
 
4
](PO
 
4
)(OH)
 
2
Related Minerals - Hey's Index Grouping:

- +
10.2.1Lüneburgite
Mg
 
3
[B
 
2
(OH)
 
6
](PO
 
4
)
 
2
· 6H
 
2
O
10.2.3Teruggite
Ca
 
4
Mg[AsO
 
4
|B
 
6
O
 
7
(OH)
 
6
]
 
2
· 12H
 
2
O
10.2.4Seamanite
Mn
2+
3
[B(OH)
 
4
](PO
 
4
)(OH)
 
2

Other Names for Cahnite

Synonyms:
Calcium Edingtonite
Other Languages:
German:Cahnit
Japanese:カーン石
Russian:Канит
Simplified Chinese:砷硼钙石
水砷硼钙石
Spanish:Cahnita

Other Information

Fluorescence in UV light:Fluoresces moderate creamy white in SW UV (Franklin).
Other Information:Readily soluble in dilute HCl.
Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Cahnite

Reference List:

- +
Palache, C. and Bauer, L. (1927) American Mineralogist: 12: 149-153.

Palache, C. (1941) American Mineralogist: 26: 429.

Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II. John Wiley and Sons, Inc., New York, 7th edition, revised and enlarged: 386-387.

American Mineralogist (1961): 46: 1077-1085.

Grew, E.S., and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).

Internet Links for Cahnite

Search Engines:
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  • External Links:
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  • Look for Cahnite on Athena Mineralogy
  • Look for Cahnite on Wikipedia
  • Look for Cahnite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Cahnite details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
  • Fabre Minerals - search for Cahnite specimens
  • Buy from David K Joyce minerals
  • SpiriferMinerals.com - high quality low prices
  • rare and unusual minerals mainly crystallized
  • Buy minerals from YourMineralCollection
  • Search for Cahnite on Well-Arranged Molecules
  • Lapis Mineral Magazin
  • Cahnite specimens for sale - minfind.com
  • Mineral Classics - Worldwide Collector Quality Minerals and Gems
  • DAKOTA MATRIX offers Cabinet and Rare Species from Worldwide Localities.
  • Rare and Unusual minerals at Mineralogical Research Company
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  • Localities for Cahnite

    The 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.
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Brazil
     
    • Goiás
    Orris, G.J., and Grauch, R.I. (2002): USGS Open-File Report 02-189.
    China
     
    • Inner Mongolia Autonomous Region
      • Ulanhad League (Chifeng Prefecture)
        • Hexigten Banner (Keshiketeng Co.)
          • Huanggang Fe-Sn deposit (Huanggangliang Mine; Huanggang Mine)
    Ottens, B. and G. Neumeier (2012) The Huanggang Mine, Inner Mongolia, China. Mineralogical Record 43:529-563
        • Linxi Co.
          • Linxi
    Ottens, B. & Bin, J. (2014): Seltene Boratmineralien aus der Inneren Mongolei, China. Lapis, 39 (7/8), 66-68.
    Italy
     
    • Latium
      • Rome Province
        • Alban Hills
    Mineralogical. Magazine, 32, 666-668
        • Rome
          • Valleranello
    http://rruff.info/cahnite/
    Japan
     
    • Honshu Island
      • Chugoku Region
        • Okayama Prefecture
          • Takahashi City
            • Bicchu-cho (Bitchu-cho)
              • Fuka
    Shiraga et al (2002), Jourmal of Mineralogical and Petrological Sciences 97,70-73(2002)
    Namibia
     
    • Otjozondjupa Region
      • Grootfontein District
        • Kombat
    Dunn, P.J. (1991), Rare minerals of the Kombat Mine, Mineralogical Record: 22(6): 421-425.
    Norway
     
    • Aust-Agder
      • Arendal
        • Arendal Iron Mines
          • Øyestad
    Bugge, J.A.W. (1951); Minerals from the skarn iron ore deposits at Arendal, Norway. I. Cahnite from Klodeborg mine. Det Kongelige Norske Videnskabers Selskab Skrifter, Forhandliger 24:79-81
    Russia
     
    • Eastern-Siberian Region
      • Transbaikalia (Zabaykalye)
        • Buriatia Republic (Buryatia)
          • Vitim Plateau
    Doklady Acad. Nauk SSSR 166,695-697(1966)
    Turkey
     
    • Aegean Region
      • Kütahya Province
        • Emet
          • Emet Borate deposit
    American Mineralogist; April 1979; v. 64; no. 3-4; p. 362-366
    C.Helvaci & R.N.Alonso (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, 9, 1-27(2000); American Mineralogist; April 1979; v. 64; no. 3-4; p. 362-366
    USA
     
    • New Jersey
      • Sussex Co.
        • Franklin Mining District
          • Franklin
    Palache, C. (1935) American Mineralogist: 26: 126; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 387; Dunn, P.J. (1995): Part5: 660-663.
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    Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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