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Alforsite

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Big Photo

Incline Sanbornite deposit, Eagle Peak, El Portal, Mariposa Co., California, USA
© Pavel M. Kartashov




Formula:
Ba
 
5
(PO
 
4
)
 
3
Cl
System:HexagonalColour:Colorless
Hardness:5
Member of:Apatite Group > Apatite Supergroup
Name:
Named by N. G. Newberry, Eric J. Essene, and Donald R. Peacor in honor of John T. Alfors [November 24, 1930 Reedley, CA, USA - December 27, 2005 Davis, CA], geologist and systematic mineralogist with the California geological Survey, USA.


Apatite Group. The barium analogue of Chlorapatite.

Classification of Alforsite

IMA status:Approved 1980
Strunz 8th edition ID:7/B.39-120
Nickel-Strunz 10th (pending) edition ID:8.BN.05

8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
N : With only large cations, (OH, etc.):RO4 = 0.33:1
Dana 8th edition ID:41.8.5.2

41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
8 : A5(XO4)3Zq
Hey's CIM Ref.:22.2.7

22 : Phosphates, Arsenates or Vanadates with other Anions
2 : Phosphates, arsenates or vanadates with chloride
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Type Occurrence of Alforsite

Co-type Localities:Big Creek, Rush Creek deposit, Big Creek-Rush Creek District, Fresno Co., California, USA
Esquire No. 7 claim, Big Creek, Rush Creek deposit, Big Creek-Rush Creek District, Fresno Co., California, USA
Place of Conservation of Type Material:National Museum of Natural History, Washington, D.C., USA, 147511.
Year of Discovery:1980
Geological Setting of type material:Contact metamorphosed barium-rich metasediments
Associated Minerals at type locality:
WitheriteWalstromiteTourmalineTitantaramelliteSanbornite
QuartzPyriteGillespiteFresnoiteFluorapatite
Celsian

Occurrences of Alforsite

Geological Setting:In lenses and bands of barium silicate metasediments developed under hornblende-pyroxene hornfels facies near the contact with granite or granodiorite.

Physical Properties of Alforsite

Lustre:Vitreous, Sub-Vitreous
Diaphaneity (Transparency):Transparent
Colour:Colorless
Streak:White
Hardness (Mohs):5
Tenacity:Brittle
Cleavage:None Observed
Density (calculated):4.80 g/cm3
Comment:Also 4.73

Crystallography of Alforsite

Crystal System:Hexagonal
Class (H-M):6/m - Dipyramidal
Space Group:P63/m
Space Group Setting:P63/m
Cell Parameters:a = 10.25Å, c = 7.64Å
Ratio:a:c = 1 : 0.745
Unit Cell Volume:V 695.14 ų (Calculated from Unit Cell)
Z:2
Morphology:Crystals are subhedral, to 0.2 mm, in very fine-grained masses.
X-Ray Powder Diffraction:
d-spacingIntensity
3.06 (100)
2.13 (40)
2.03 (30)
1.928 (30)
1.566 (30)
1.336 (30)
1.077 (30)
Comments:Synthetic material

Optical Data of Alforsite

Type:Uniaxial (-)
RI values: nω = 1.700 nε = 1.701
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:High
Optical Extinction:Parallel
Pleochroism:Non-pleochroic

Chemical Properties of Alforsite

Formula:
Ba
 
5
(PO
 
4
)
 
3
Cl
Essential elements:Ba, Cl, O, P
All elements listed in formula:Ba, Cl, O, P

Relationship of Alforsite to other Species

Member of:Apatite Group > Apatite Supergroup
Other Members of Group:

- +
Carbonate-rich Fluorapatite
Ca
 
5
(PO
 
4
,CO
 
3
)
 
3
(F,O)
Chlorapatite
Ca
 
5
(PO
 
4
)
 
3
Cl
Fluorapatite
Ca
 
5
(PO
 
4
)
 
3
F
Hydroxylapatite
Ca
 
5
(PO
 
4
)
 
3
(OH)
Hydroxylapatite-M
Ca
 
5
(PO
 
4
)
 
3
OH
Johnbaumite
Ca
 
5
(AsO
 
4
)
 
3
OH
Johnbaumite-M
Ca
 
5
(AsO
 
4
)
 
3
OH
Mimetite
Pb
 
5
(AsO
 
4
)
 
3
Cl
Mimetite-2M
Mimetite-M
Pb
 
5
(AsO
 
4
)
 
3
Cl
Miyahisaite
(Sr,Ca)
 
2
Ba
 
3
(PO
 
4
)
 
3
F
Pyromorphite
Pb
 
5
(PO
 
4
)
 
3
Cl
Stronadelphite
Sr
 
5
(PO
 
4
)
 
3
F
Svabite
Ca
 
5
(AsO
 
4
)
 
3
F
Turneaureite
Ca
 
5
(AsO
 
4
)
 
3
Cl
Vanadinite
Pb
 
5
(VO
 
4
)
 
3
Cl
Common Associates:
WitheriteWalstromiteTourmalineTitantaramelliteSanbornite
QuartzPyriteGillespiteFresnoiteFluorapatite
Celsian
Related Minerals - Nickel-Strunz Grouping):

- +
8.BN.05Belovite-(Ce)
NaCeSr
 
3
(PO
 
4
)
 
3
F
8.BN.05Carbonate-rich Fluorapatite
Ca
 
5
(PO
 
4
,CO
 
3
)
 
3
(F,O)
8.BN.05Carbonate-rich Hydroxylapatite
Ca
 
5
(PO
 
4
,CO
 
3
)
 
3
(OH,O)
8.BN.05Chlorapatite
Ca
 
5
(PO
 
4
)
 
3
Cl
8.BN.05Mimetite-M
Pb
 
5
(AsO
 
4
)
 
3
Cl
8.BN.05Johnbaumite-M
Ca
 
5
(AsO
 
4
)
 
3
OH
8.BN.05Fluorapatite
Ca
 
5
(PO
 
4
)
 
3
F
8.BN.05Hedyphane
Pb
 
3
Ca
 
2
(AsO
 
4
)
 
3
Cl
8.BN.05Hydroxylapatite
Ca
 
5
(PO
 
4
)
 
3
(OH)
8.BN.05Johnbaumite
Ca
 
5
(AsO
 
4
)
 
3
OH
8.BN.05Mimetite
Pb
 
5
(AsO
 
4
)
 
3
Cl
8.BN.05Morelandite
Ca
 
2
Ba
 
3
(AsO
 
4
)
 
3
Cl
8.BN.05Pyromorphite
Pb
 
5
(PO
 
4
)
 
3
Cl
8.BN.05Fluorstrophite
SrCaSr
 
3
(PO
 
4
)
 
3
F
8.BN.05Svabite
Ca
 
5
(AsO
 
4
)
 
3
F
8.BN.05Turneaureite
Ca
 
5
(AsO
 
4
)
 
3
Cl
8.BN.05Vanadinite
Pb
 
5
(VO
 
4
)
 
3
Cl
8.BN.05Belovite-(La)
NaLaSr
 
3
(PO
 
4
)
 
3
F
8.BN.05Deloneite
(Na
 
0.5
REE
 
0.25
Ca
 
0.25
)(Ca
 
0.75
REE
 
0.25
)Sr
 
1.5
(CaNa
 
0.25
REE
 
0.25
)(PO
 
4
)
 
3
F
 
0.5
(OH)
 
0.5
8.BN.05Fluorcaphite
SrCaCa
 
3
(PO
 
4
)
 
3
F
8.BN.05Kuannersuite-(Ce)
NaCeBa
 
3
(PO
 
4
)
 
3
F
 
0.5
Cl
 
0.5
8.BN.05Hydroxylapatite-M
Ca
 
5
(PO
 
4
)
 
3
OH
8.BN.05Phosphohedyphane
Ca
 
2
Pb
 
3
(PO
 
4
)
 
3
Cl
8.BN.05Stronadelphite
Sr
 
5
(PO
 
4
)
 
3
F
8.BN.05Fluorphosphohedyphane
Ca
 
2
Pb
 
3
(PO
 
4
)
 
3
F
8.BN.05Miyahisaite
(Sr,Ca)
 
2
Ba
 
3
(PO
 
4
)
 
3
F
8.BN.10Arctite
Na
 
2
Ca
 
4
(PO
 
4
)
 
3
F
Related Minerals - Hey's Index Grouping:

- +
22.2.1Sampleite
NaCaCu
 
5
(PO
 
4
)
 
4
Cl · 5H
 
2
O
22.2.2Lavendulan
NaCaCu
 
5
(AsO
 
4
)
 
4
Cl · 5H
 
2
O
22.2.3Chlorapatite
Ca
 
5
(PO
 
4
)
 
3
Cl
22.2.4Turneaureite
Ca
 
5
(AsO
 
4
)
 
3
Cl
22.2.5Shubnikovite
Ca
 
2
Cu
 
8
(AsO
 
4
)
 
6
(OH)Cl · 7H
 
2
O
22.2.6Richelsdorfite
Ca
 
2
Cu
 
5
Sb(AsO
 
4
)
 
4
(OH)
 
6
Cl · 6H
 
2
O
22.2.8Morelandite
Ca
 
2
Ba
 
3
(AsO
 
4
)
 
3
Cl
22.2.9Pyromorphite
Pb
 
5
(PO
 
4
)
 
3
Cl
22.2.10Mimetite
Pb
 
5
(AsO
 
4
)
 
3
Cl
22.2.11Mimetite-M
Pb
 
5
(AsO
 
4
)
 
3
Cl
22.2.12Sahlinite
Pb
 
14
(AsO
 
4
)
 
2
O
 
9
Cl
 
4
22.2.13Georgiadèsite
Pb
 
4
(AsO
 
3
)Cl
 
4
(OH)
22.2.14Vanadinite
Pb
 
5
(VO
 
4
)
 
3
Cl
22.2.15Kombatite
Pb
 
14
(VO
 
4
)
 
2
O
 
9
Cl
 
4
22.2.16Leningradite
PbCu
 
3
(VO
 
4
)
 
2
Cl
22.2.17Hedyphane
Pb
 
3
Ca
 
2
(AsO
 
4
)
 
3
Cl
22.2.18Nealite
Pb
 
4
Fe
2+
 
(As
3+
 
O
 
3
)
 
2
Cl
 
4
 · 2H
 
2
O

Other Names for Alforsite

Synonyms:
IMA1980-039
Other Languages:
German:Alforsit
Spanish:Alforsita

Other Information

Fluorescence in UV light:Not fluorescent, but bright purple/violet cathodluminescence
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 Alforsite

Reference List:

- +
Newberry, N.G., Essene, E.J., and Peacor, D.R. (1981) Alforsite, a new member of the apatite group, the barium analogue of chlorapatite. American Mineralogist: 66: 1050-1053.

Acta Crystallographica:: B35: 2382-2384.

Internet Links for Alforsite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Alforsite details from Handbook of Mineralogy (PDF)
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    • Localities for Alforsite

    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.
    Canada
     
    • Yukon Territory
      • Watson Lake Mining District
        • Itsy Mts
          • MacMillian Pass
    		McNeil, L.A., Peterson, R.C., Färber, G., Groat, L. & Witzke, T. (2013) Mineralogical studies of a low-temperature barium-rich skarn deposit, Gunn claim, Yukon Territory. Abstract with Program, Min. Ass. Canada Annual Mtg. Winnipeg, May 2013.
    Mexico
     
    • Baja California (Baja California Norte; BC Norte)
      • Tres Pozos
    		Anthony, Bideaux, Bladh, Nichols: "Handbook of Mineralogy", Vol. 4, 2000; American Mineralogist, Volume 69, pages 358-373, 1984
    USA
     
    • California
      • Fresno Co.
        • Big Creek-Rush Creek District
          • Rush Creek deposit
    		Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 314.
    [MinRec 33:161]; American Mineralogist (1981), Volume 66, pages 1050-1053
      • Mariposa Co.
        • El Portal
          • Eagle Peak
    		Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 315; Mineralogical Record (1999): 30: 414; American Mineralogist (1981), Volume 66, pages 1050-1053.
      • Tulare Co.
        • Exeter area
          • Chickencoop Canyon
    		Mineralogical Record: 34(2): 159-166
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