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About MillisiteHide

(Na,K)CaAl6(PO4)4(OH)9 · 3H2O
White, light gray; colourless in transmitted light.
Specific Gravity:
Crystal System:
Member of:
Named in 1942 by Esper Signius Larsen III in honor of Mr. F. T. Millis of Lehi, Utah County, Utah, who had discovered and was an early miner of the variscite locality.
Wardite Group.
Closely related to wardite.
Needs reinvestigation by modern methods.

Classification of MillisiteHide

Approved, 'Grandfathered' (first described prior to 1959)

D : Phosphates, etc. with additional anions, with H2O
L : With large and medium-sized cations, (OH, etc.):RO4 = 2:1

7 : (AB)2(XO4)Zq·xH2O

19 : Phosphates
8 : Phosphates of Al and other metals

Physical Properties of MillisiteHide

White, light gray; colourless in transmitted light.
5½ on Mohs scale
2.83 g/cm3 (Measured)    2.87 g/cm3 (Calculated)

Optical Data of MillisiteHide

Biaxial (+)
RI values:
nα = 1.584 nβ = 1.598 nγ = 1.602
Max Birefringence:
δ = 0.018
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of MillisiteHide

(Na,K)CaAl6(PO4)4(OH)9 · 3H2O
IMA Formula:
NaCaAl6(PO4)4(OH)9 · 3H2O

Crystallography of MillisiteHide

Crystal System:
Cell Parameters:
a = 7.00 Å, c = 18.99 Å
a:c = 1 : 2.713
Unit Cell V:
930.51 ų (Calculated from Unit Cell)
Chalcedonic crusts or spherules with a fine-fibrous structure.
Other values reported: 7.00, 19.07 (Owens et al., 1960).

X-Ray Powder DiffractionHide

Powder Diffraction Data:
6.6 (40)
4.84 (100b)
3.93 (30)
3.48 (30)
3.09 (60b)
2.98 (80b)
2.81 (80b)
Similar to wardite.

Type Occurrence of MillisiteHide

Synonyms of MillisiteHide

Other Language Names for MillisiteHide

Simplified Chinese:磷铝钙钠石

Relationship of Millisite to other SpeciesHide

Member of:
Other Members of this group:
CyriloviteNaFe3+3(PO4)2(OH)4 · 2H2OTet. 4 2 2 : P41 21 2
FluorowarditeNaAl3(PO4)2F2(OH)2(H2O)2 Tet. 4 2 2 : P41 21 2
WarditeNaAl3(PO4)2(OH)4 · 2H2OTet. 4 2 2 : P41 21 2

Common AssociatesHide

Apatite"Apatite" is a field term for unidentified calcium phosphate members of the apatite group.
TurquoiseCu(Al,Fe3+)6(PO4)4(OH)8 · 4H2O
WarditeNaAl3(PO4)2(OH)4 · 2H2O
WavelliteAl3(PO4)2(OH,F)3 · 5H2O
Associated Minerals Based on Photo Data:
Wardite19 photos of Millisite associated with Wardite on mindat.org.
Crandallite18 photos of Millisite associated with Crandallite on mindat.org.
Variscite12 photos of Millisite associated with Variscite on mindat.org.
Gordonite5 photos of Millisite associated with Gordonite on mindat.org.
Montgomeryite4 photos of Millisite associated with Montgomeryite on mindat.org.
Carbonate-rich Apatite4 photos of Millisite associated with Carbonate-rich Apatite on mindat.org.
Apatite1 photo of Millisite associated with Apatite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

8.DL.05FoggiteCaAl(PO4)(OH)2 · H2OOrth. mmm (2/m 2/m 2/m)
8.DL.10CyriloviteNaFe3+3(PO4)2(OH)4 · 2H2OTet. 4 2 2 : P41 21 2
8.DL.10WarditeNaAl3(PO4)2(OH)4 · 2H2OTet. 4 2 2 : P41 21 2
8.DL.15Agardite-(Nd)NdCu6(AsO4)3(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.15Agardite-(Y)YCu6(AsO4)3(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.15Agardite-(Ce)CeCu6(AsO4)3(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.15Agardite-(La)LaCu6(AsO4)3(OH)6 · 3H2OHex. 6/m
8.DL.15GoudeyiteAlCu6(AsO4)3(OH)6 · 3H2OHex.
8.DL.15MixiteBiCu6(AsO4)3(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.15Petersite-(Y)(Y,Ce,Nd)Cu6(PO4)3(OH)6 · 3H2OHex.
8.DL.15ZálesíiteCaCu6(AsO4)2(AsO3OH)(OH)6 · 3H2OHex.
8.DL.15Plumboagardite(Pb,REE,Ca)Cu6(AsO4)3(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.15CalciopetersiteCaCu6(PO4)2(PO3OH)(OH)6 · 3H2OHex. 6/m : P63/m
8.DL.20DugganitePb3Zn3(AsO4)2(TeO6)Trig. 3 2 : P3 2 1
8.DL.20KuksitePb3Zn3(PO4)2(TeO6)Trig. 3 2 : P3 2 1
8.DL.20WallkilldelliteCa2Mn2+3(AsO4)2(OH)4 · 9H2OHex.
8.DL.20Wallkilldellite-(Fe)(Ca,Cu)4Fe2+6(AsO4,SiO4)4(OH,O)8 · 18H2OHex.
8.DL.25AngastoniteCaMgAl2(PO4)2(OH)4 · 7H2OTric. 1 : P1

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

19.8.1MontebrasiteLiAl(PO4)(OH)Tric. 1 : P1
19.8.2BrazilianiteNaAl3(PO4)2(OH)4Mon. 2/m : P2/b
19.8.3WarditeNaAl3(PO4)2(OH)4 · 2H2OTet. 4 2 2 : P41 21 2
19.8.4TancoiteLiNa2Al(PO4)(HPO4)(OH)Orth. mmm (2/m 2/m 2/m) : Pbca
19.8.6TinsleyiteKAl2(PO4)2(OH) · 2H2OMon.
19.8.7Taranakite(K,NH4)Al3(PO4)3(OH) · 9H2OTrig. 3m (3 2/m) : R3c
19.8.8FrancoanelliteK3Al5(PO4)2(HPO4)3 · 12H2OTrig.
19.8.9GordoniteMgAl2(PO4)2(OH)2 · 8H2OTric. 1 : P1
19.8.10AldermaniteMg5Al12(PO4)8(OH)22 · 32H2OOrth.
19.8.11OveriteCaMgAl(PO4)2(OH) · 4H2OOrth. mmm (2/m 2/m 2/m) : Pbca
19.8.12MontgomeryiteCa4MgAl4(PO4)6(OH)4 · 12H2OMon. 2 : B2
19.8.14FoggiteCaAl(PO4)(OH)2 · H2OOrth. mmm (2/m 2/m 2/m)
19.8.15GatumbaiteCaAl2(PO4)2(OH)2 · H2OMon. 2/m : P2/m
19.8.16CrandalliteCaAl3(PO4)(PO3OH)(OH)6Trig. 3m (3 2/m) : R3m
19.8.17Matulaite(Fe3+,Al)Al7(PO4)4(PO3OH)2(OH)8(H2O)8 · 8H2OMon.
19.8.21EnglishiteK3Na2Ca10Al15(PO4)21(OH)7 · 26H2OMon. 2/m
19.8.22KleemaniteZnAl2(PO4)2(OH)2 · 3H2OMon.
19.8.23MantienneiteKMg2Al2Ti(PO4)4(OH)3 · 15H2OOrth.
19.8.24PaulkerriteK(Mg,Mn2+)2(Fe3+,Al,Ti,Mg)2Ti(PO4)4(OH)3 · 15H2OOrth. mmm (2/m 2/m 2/m) : Pbca

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for MillisiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Larsen, Esper S., III and Shannon, Wincent Earl (1930) American Mineralogist: 15: 307-337.
Larsen, Esper S., III (1942) American Mineralogist: 27: 294.
Palache, Charles, Berman, Harry, & Frondel, Clifford (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, 1124 pp.: 941-942.
Owens, J. P., Z. S. Altschuler, and R. Berman (1960) Millisite in phosphorite from Homeland, Florida. American Mineralogist: 45: 547-561.
Wilson, Wendell E. (2010) The Clay Canyon variscite mine: Fairfield, Utah has been famous among mineral collectors for well over a century as the source of the world's finest specimens of variscite,, Mineralogical Record.
Mineralogical Magazine: 37: 598-605.

Internet Links for MillisiteHide

Localities for MillisiteHide

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

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Doak, B. W., Gallagher, P. J., Evans, L., Muller, F. B. (1965) Low-temperature calcination of “C”-grade phosphate from christmas island: I. Growth and yield characteristics. New Zealand journal of agricultural research, 8(1), 15-29. Trueman, N. A. (1965) The phosphate, volcanic and carbonate rocks of Christmas Island (Indian Ocean). Journal of the Geological Society of Australia, 12(2), 261-283.
  • South Australia
    • Eyre peninsula
      • Middleback Range
        • Iron Duke Complex
Francis, G.L., 2010. Minerals from the South Middleback Range deposits 2003-2008. (self published) 44pp.
        • Iron Knob
Pilkington, E. S., Segnit, E. R., Watts, J. and Francis, G. (1979): Kleemanite, a new zinc aluminium phosphate. Mineralogical Magazine 43, 93-95.
  • Western Australia
    • Upper Gascoyne Shire
      • Woodlands station
Nickel, E. H. et al. (2008): The Woodlands variscite-gold occurrence in the north Gascoyne region of Western Australia. Australian Journal of Mineralogy 14, 27-36.
  • Carinthia
    • Millstatt lake ridge
      • Spittal
        • Millstatt lake
Walter, F. (1998): Exkursion E4 am 27.9.1998 - MinPet 98 (Pörtschach am Wörthersee/Kärnten) - Die Pegmatite des Millstätter See-Rückens. Mitt. Österr. Mineral. Ges. 143, 437-450. [http://www.uibk.ac.at/mineralogie/oemg/bd_143/143minpet98_437-450.pdf]; Collection of NHM, Vienna
        • Wolfsberg
Pichler (2009)
  • Western Province
Handbook of Mineralogy - Anthony, Bideaux, Bladh, Nichols
  • Thiès Region
  • Skåne
    • Bromölla
      • Näsum
Hansen, S. & Landa-Canovas, A. (1994): Childrenite and millisite from Västanå Mine, Skåne, Sweden. Geologiska Föreningens i Stockholm Förhandlingar 116: 92.
  • Florida
    • Polk Co.
      • Central Florida Phosphate District (Bone Valley)
        • Homeland
Denicourt, R., Micromounters of New England program, NE meeting program, May 1984; Marc V. Hurst (2012) Central Florida Phosphate District. Southeastern Geological Society Field Trip Guidebook No. 57
Owens, J.P., Z.S. Altschuler, and R. Berman (1960) Millisite in phosphorite from Homeland, Florida. American Mineralogist: 45: 547-561.; Altschuler, Z. S., Jaffe, E. B., and Cuttitta, Frank, (1956), The aluminum phosphate zone of the Bone Valley formation, Florida, and its uranium deposits: U.S. Geol. Survey Prof. Paper 300, p. 495-504.
        • Noralyn/Phosphoria Mines (IMC-Agrico)
Marc V. Hurst (2012) Central Florida Phosphate District. Southeastern Geological Society Field Trip Guidebook No. 57
  • Utah
    • Tooele Co.
      • Stansbury Mts
UGMS Bull 117 Minerals and Mineral Localities of Utah
    • Utah Co.
      • Oquirrh Mts
        • Fairfield
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: 941, 942, 958; UGMS Bull 117 Minerals and Mineral Localities of Utah
Rocks & Minerals (1970): 45(11): 667-674.; Wilson, W. (2010): The Clay Canyon Variscite Mine, Fairfield Utah. Mineralogical Record. 41:321-349.
Mineral and/or Locality  
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