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Swaknoite

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Formula:
(NH4)2Ca(HPO4)2 · H2O
Colour:
White
Lustre:
Vitreous
Hardness:
1½ - 2
Specific Gravity:
1.91
Crystal System:
Orthorhombic
Name:
The name derives from the acronym SWAKNO, for the Suid West Afrika Karst Navorsing Organisatsie (Namibia), a speleological association whose members noted the presence of a wide variety of minerals in the Arnhem cave (type locality).
This page provides mineralogical data about Swaknoite.


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Classification of SwaknoiteHide

Approved
Approval Year:
1991
8.CJ.10

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
J : With only large cations
39.3.4.1

39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
3 : Miscellaneous

Pronounciation of SwaknoiteHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of SwaknoiteHide

Vitreous
Transparency:
Transparent
Colour:
White
Hardness:
1½ - 2 on Mohs scale
Tenacity:
Brittle
Density:
1.91 g/cm3 (Measured)    1.89 g/cm3 (Calculated)

Optical Data of SwaknoiteHide

Type:
Biaxial (-)
RI values:
nα = 1.506 nβ = 1.510 nγ = 1.512
2V:
Measured: 65° to 70°, Calculated: 70°
Max Birefringence:
δ = 0.006
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
none

Chemical Properties of SwaknoiteHide

Formula:
(NH4)2Ca(HPO4)2 · H2O
IMA Formula:
(NH4)2Ca(PO3OH)2 · H2O

Crystallography of SwaknoiteHide

Crystal System:
Orthorhombic
Cell Parameters:
a = 20.95 Å, b = 7.4 Å, c = 6.47 Å
Ratio:
a:b:c = 2.831 : 1 : 0.874
Unit Cell V:
1,003.04 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals are elongate [001] and exhibit {110}, (100), {111}, and possibly {001}. Needle-like crystals up to 1 mm long and up to 10 μm wide, commonly grouped as rosettes.

Type Occurrence of SwaknoiteHide

General Appearance of Type Material:
White coatings comprised of needle-like crystals up to 1 mm long and up to 10 μm wide, commonly grouped as rosettes.
Place of Conservation of Type Material:
State Museum, Windhoek, Namibia, and in the Transvaal Museum, Pretoria, South Africa.
Geological Setting of Type Material:
Cave with dolomite walls.
Associated Minerals at Type Locality:

Synonyms of SwaknoiteHide

Other Language Names for SwaknoiteHide

German:Swaknoit
Spanish:Swaknoita

Related Minerals - Nickel-Strunz GroupingHide

8.CJ.CaesiumpharmacosideriteCsFe4[(AsO4)3(OH)4]·4H2OIso. 4 3m : P4 3m
8.CJ.05StercoriteNa(NH4)HPO4 · 4H2OTric.
8.CJ.10Mundrabillaite(NH4)2Ca(HPO4)2 · H2OMon. m : Pm
8.CJ.15NabaphiteNaBaPO4 · 9H2OIso.
8.CJ.15NastrophiteNa(Sr,Ba)PO4 · 9H2O
8.CJ.20HaidingeriteCaHAsO4 · H2OOrth. mmm (2/m 2/m 2/m) : Pbcn
8.CJ.25VladimiriteCa4(AsO4)2(AsO3OH) · 4H2OMon. 2/m : P21/b
8.CJ.30FerrarisiteCa5(AsO4)2(HAsO4)2 · 9H2OTric. 1 : P1
8.CJ.35Machatschkiite(Ca,Na)6(AsO4)(HAsO4)3(PO4,SO4) · 15H2OHex.
8.CJ.40PhaunouxiteCa3(AsO4)2 · 11H2OTric.
8.CJ.40RauenthaliteCa3(AsO4)2 · 10H2OTric. 1 : P1
8.CJ.45Brockite(Ca,Th,Ce)PO4 · H2OHex. 6 2 2 : P62 2 2
8.CJ.45Grayite(Th,Pb,Ca)(PO4) · H2OHex. 6 2 2 : P62 2 2
8.CJ.45Rhabdophane-(Ce)(Ce,La)(PO4) · H2OHex. 6 2 2 : P62 2 2
8.CJ.45Rhabdophane-(La)(La,Ce)(PO4) · H2OHex. 6 2 2 : P62 2 2
8.CJ.45Rhabdophane-(Nd)(Nd,Ce,La)(PO4) · H2OHex. 6 2 2 : P62 2 2
8.CJ.45Tristramite(Ca,U,Fe)(PO4,SO4) · 2H2OHex.
8.CJ.45Smirnovskite(Th,Ca)PO4 · nH2OHex. 6 2 2 : P62 2 2
8.CJ.50ArdealiteCa2(HPO4)(SO4) · 4H2OMon. m : Bb
8.CJ.50BrushiteCa(HPO4) · 2H2OMon. m : Bb
8.CJ.50Churchite-(Y)Y(PO4) · 2H2OMon. 2/m : B2/b
8.CJ.50PharmacoliteCa(HAsO4) · 2H2OMon. m
8.CJ.50Churchite-(Nd)Nd(PO4) · 2H2OMon.
8.CJ.55McneariteNaCa5(AsO4)(HAsO4)4 · 4H2OTric.
8.CJ.60DorfmaniteNa2HPO4 · 2H2OOrth.
8.CJ.65SincositeCa(VO)2(PO4)2 · 5H2OTet. 4/mmm (4/m 2/m 2/m) : P42/nnm
8.CJ.65BariosincositeBa(VO)2(PO4)2 · 4H2OTet.
8.CJ.70CatalanoiteNa2(HPO4) · 8H2OOrth. mmm (2/m 2/m 2/m) : Ibca
8.CJ.75GuériniteCa5(AsO4)2(HAsO4)2 · 9H2OMon. 2/m : P21/b
8.CJ.85NingyoiteCaU(PO4)2 · 1-2H2OOrth.

Other InformationHide

Notes:
Soluble in H2O.
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 SwaknoiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Martini, J.E.J. (1992) Swaknoite [Ca(NH4)2·(HPO4)2·H2O, orthorhombic]: A new mineral from Arnhem cave, Namibia. Bulletin of the South African Speleological Association: 32: 72-74.
Jambor, John L and Puziewicz, Jacek (1993) New Mineral Names. American Mineralogist: 78: 1108-1112.
New Minerals (1997), New Minerals 1990-1994.

Internet Links for SwaknoiteHide

Localities for SwaknoiteHide

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.
Namibia (TL)
 
  • Khomas Region
    • Windhoek District
Martini, J.E.J. (1992) Swaknoite [Ca(NH4)2·(HPO4)2·H2O, orthorhombic]: A new mineral from Arnhem cave, Namibia. Bulletin of the South African Speleological Association: 32: 72-74.
Mineral and/or Locality  
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