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Cahnite

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Franklin, Franklin Mining District, Sussex Co., New Jersey, USA

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Formula:
Ca
 
2
[B(OH)
 
4
](AsO
 
4
)
System:TetragonalColour:Colourless to white; ...
Hardness:3
Name:After Mr. Lazard Cahn (1865-1940) mineral collector and 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

Physical Properties of Cahnite

Lustre:Vitreous
Diaphaneity (Transparency):Transparent
Colour:Colourless to white; colourless in transmitted light.
Hardness (Mohs):3
Tenacity:Brittle
Cleavage:Perfect
On {110}
Density (measured):3.156 g/cm3

Crystallography of Cahnite

Crystal System:Tetragonal
Class (H-M):4 - Disphenoidal
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)
Morphology:Single untwinned crystals rare, pseudo-tetragonal 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.

Optical Data of Cahnite

Type:Uniaxial (+)
RI values: nω = 1.662 nε = 1.663
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.
Comments:Exhibits abnormal interference colours.

Chemical Properties of Cahnite

Formula:
Ca
 
2
[B(OH)
 
4
](AsO
 
4
)
Essential elements:As, B, Ca, H, O
All elements listed in formula:As, B, Ca, H, O

Relationship of Cahnite to other Species

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

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

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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.
    Hide Locality List
    (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
    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
            • Bitchu-cho-fuka (Bicchu-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 (Buryatia) Republic
          • 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 1993-2013. 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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