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Paracelsian

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02698280014977408313023.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
05017790016009042471176.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
07167240015216484411139.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
05676970014950646515114.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
00399230016004093331992.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
07167240015216484411139.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
02698280014977408313023.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
00399230016004093331992.jpg
Paracelsian

Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK
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About ParacelsianHide

Formula:
Ba(Al2Si2O8)
Colour:
Colourless to white, light yellow tint.
Lustre:
Vitreous
Hardness:
6
Crystal System:
Monoclinic
Member of:
Feldspar Group
Name:
From the Greek for "near" and "Celsian" in allusion to its relationship to that species.
Polymorph of:
Celsian, Hexacelsian
Feldspar Group. The pseudo-orthorhombic (the monoclinic angle is 90.01°) dimorph of Celsian.

Paracelsian appears to be a metastable phase; it changes monotropically through hexacelsian to celsian at temperatures at least as low as 500°C and possibly at lower temperatures also (Lin & Foster, 1968).

The morphology of the crystals makes them very similar to some chisel-shaped habits of topaz and danburite.


Classification of ParacelsianHide

IMA status:
Approved, 'Grandfathered' (first described prior to 1959)
Strunz 8th ed.:
8/J.06-70
Nickel-Strunz 10th (pending) ed.:
9.FA.40

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
Dana 8th ed.:
76.1.5.1

76 : TECTOSILICATES Al-Si Framework
1 : Al-Si Framework with Al-Si frameworks
Hey's CIM Ref.:
16.12.5

16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn

Pronounciation of ParacelsianHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of ParacelsianHide

Lustre:
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless to white, light yellow tint.
Hardness:
6 on Mohs scale
Cleavage:
Poor/Indistinct
Poor cleavage {110} (unusual for feldspars).
Fracture:
Sub-Conchoidal

Optical Data of ParacelsianHide

Type:
Biaxial (-)
RI values:
nα = 1.570 nβ = 1.582 nγ = 1.587
Max Birefringence:
δ = 0.017
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v

Chemical Properties of ParacelsianHide

Formula:
Ba(Al2Si2O8)
Elements listed:
Al, Ba, O, Si - search for minerals with similar chemistry
Common Impurities:
Fe,Mg,Ca,Na,K,H2O

Crystallography of ParacelsianHide

Crystal System:
Monoclinic
Cell Parameters:
a = 9.07 Å, b = 9.58 Å, c = 8.57 Å
β = 90.01°
Ratio:
a:b:c = 0.947 : 1 : 0.895
Unit Cell V:
744.65 ų (Calculated from Unit Cell)
Morphology:
Crystals prismatic, with {110} and {120} dominant, and with chisel-shaped terminations formed by {201}.
Twinning:
Twinning on {100}, simple; on {201}, lamellar.
Comment:
Pseudo-orthorhombic.

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0000997ParacelsianChiari G, Gazzoni G, Craig J R, Gibbs G V, Louisnathan S J (1985) Two independent refinements of the structure of paracelsian, BaAl2Si2O8 American Mineralogist 70 969-9741985Benallt Mine, Carnarvonshire, U.K.0293
0000998ParacelsianChiari G, Gazzoni G, Craig J R, Gibbs G V, Louisnathan S J (1985) Two independent refinements of the structure of paracelsian, BaAl2Si2O8 American Mineralogist 70 969-9741985Benallt Mine, Carnarvonshire, U.K.0293
0009156ParacelsianSmith J V (1953) The crystal structure of paracelsian, BaAl2Si2O8 Acta Crystallographica 6 613-6201953Benallt Mine, near Rhiw, Carnarvonshire, U.K.0293
CIF Raw Data - click here to close

Type Occurrence of ParacelsianHide

Synonyms of ParacelsianHide

Ba Feldspar (in part)

Other Language Names for ParacelsianHide

Relationship of Paracelsian to other SpeciesHide

Member of:
Feldspar Group
Other Members of this group:
Alkali FeldsparA subgroup of the Feldspar Group, poor in calcium, and mostly rich in potassium.
AmazoniteK(AlSi3O8)
Andesine(Na,Ca)[Al(Si,Al)Si2O8]Tric.
AnorthiteCa(Al2Si2O8)Tric. 1 : P1
BanalsiteNa2BaAl4Si4O16Orth. mm2 : Iba2
Buddingtonite(NH4)(AlSi3O8)Mon. 2 : P21
Bytownite(Ca,Na)[Al(Al,Si)Si2O8]Tric.
DmisteinbergiteCa(Al2Si2O8)Trig. 3 2 : P3 1 2
FerrisanidineK[Fe3+Si3O8]Mon. 2/m : B2/m
FilatoviteK(Al,Zn)2(As,Si)2O8Mon. 2/m
HexacelsianBaAl2Si2O8Hex. 6/mmm (6/m 2/m 2/m) : P63/mcm
KokchetaviteK(AlSi3O8)Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm
KumdykoliteNa(AlSi3O8)Orth. mmm (2/m 2/m 2/m) : Pnnm
Labradorite(Ca,Na)[Al(Al,Si)Si2O8]
Oligoclase(Na,Ca)[Al(Si,Al)Si2O8]
ReedmergneriteNaBSi3O8Tric.
SlawsoniteSr(Al2Si2O8)Mon. 2/m : P21/b
StronalsiteNa2SrAl4Si4O16Orth.
SunstoneA variety of feldspar (microcline or oligoclase, more rarely labradorite) that has schiller, ...
SvyatoslaviteCa(Al2Si2O8)Orth.
Unnamed (New Ordered Member of the Alkali Feldspar Series)KNa(Si6Al2)O16Mon. m

Related Minerals - Nickel-Strunz GroupingHide

9.FA.05KaliophiliteKAlSiO4Trig. 3 : P3
9.FA.05KalsiliteKAlSiO4Hex. 6 2 2 : P63 2 2
9.FA.05NephelineNa3K(Al4Si4O16)Hex. 6 : P63
9.FA.05Panunzite(K,Na)AlSiO4Hex. 6 : P63
9.FA.05TrikalsiliteK2NaAl3(SiO4)3Hex.
9.FA.05Yoshiokaite(Ca,Na)[Al(Al,Si)O4]Trig. 3 : P3
9.FA.05MegakalsiliteKAlSiO4Hex. 6 : P63
9.FA.10MalinkoiteNaBSiO4Hex. 6 : P63
9.FA.15VirgiliteLiAlSi2O6Hex. 6 2 2 : P62 2 2
9.FA.25LisitsyniteKBSi2O6Orth. 2 2 2 : P2 2 2
9.FA.30AdulariaKAlSi3O8Mon.
9.FA.30Anorthoclase(Na,K)AlSi3O8Tric.
9.FA.30Buddingtonite(NH4)(AlSi3O8)Mon. 2 : P21
9.FA.30CelsianBa(Al2Si2O8)Mon. 2/m
9.FA.30Hyalophane(K,Ba)[Al(Si,Al)Si2O8]Mon.
9.FA.30MicroclineK(AlSi3O8)Tric. 1
9.FA.30OrthoclaseK(AlSi3O8)Mon. 2/m : B2/m
9.FA.30SanidineK(AlSi3O8)Mon. 2/m : B2/m
9.FA.30RubiclineRb(AlSi3O8)Tric.
9.FA.30MonalbiteNaAlSi3O8Mon. 2/m : B2/m
9.FA.35AlbiteNa(AlSi3O8)Tric. 1
9.FA.35Andesine(Na,Ca)[Al(Si,Al)Si2O8]Tric.
9.FA.35AnorthiteCa(Al2Si2O8)Tric. 1 : P1
9.FA.35Bytownite(Ca,Na)[Al(Al,Si)Si2O8]Tric.
9.FA.35Labradorite(Ca,Na)[Al(Al,Si)Si2O8]
9.FA.35Oligoclase(Na,Ca)[Al(Si,Al)Si2O8]
9.FA.35ReedmergneriteNaBSi3O8Tric.
9.FA.45SvyatoslaviteCa(Al2Si2O8)Orth.
9.FA.45KumdykoliteNa(AlSi3O8)Orth. mmm (2/m 2/m 2/m) : Pnnm
9.FA.50SlawsoniteSr(Al2Si2O8)Mon. 2/m : P21/b
9.FA.55LisetiteCaNa2Al4Si4O16Orth. mm2
9.FA.60BanalsiteNa2BaAl4Si4O16Orth. mm2 : Iba2
9.FA.60StronalsiteNa2SrAl4Si4O16Orth.
9.FA.65DanburiteCaB2Si2O8Orth. mmm (2/m 2/m 2/m)
9.FA.65MaleeviteBaB2Si2O8Orth. mmm (2/m 2/m 2/m) : Pnma
9.FA.65PekoviteSrB2Si2O8Orth. mmm (2/m 2/m 2/m) : Pnma
9.FA.70Lingunite(Na,Ca)AlSi3O8Tet. 4/m : I4/m
9.FA.75KokchetaviteK(AlSi3O8)Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm

Related Minerals - Dana Grouping (8th Ed.)Hide

76.1.5.2SlawsoniteSr(Al2Si2O8)Mon. 2/m : P21/b

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

16.12.1StronalsiteNa2SrAl4Si4O16Orth.
16.12.2SlawsoniteSr(Al2Si2O8)Mon. 2/m : P21/b
16.12.3BrewsteriteMon.
16.12.4CelsianBa(Al2Si2O8)Mon. 2/m
16.12.6CymriteBaAl2Si2(O,OH)8 · H2OMon.
16.12.7EdingtoniteBa[Al2Si3O10] · 4H2OOrth. 2 2 2 : P21 21 21
16.12.8BanalsiteNa2BaAl4Si4O16Orth. mm2 : Iba2
16.12.9Harmotome(Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2OMon. 2/m : P21/m
16.12.10Hyalophane(K,Ba)[Al(Si,Al)Si2O8]Mon.
16.12.11BalipholiteBaLiMg2Al3(Si2O6)2(OH)4Orth.
16.12.12ArmeniteBaCa2Al6Si9O30 · 2H2OOrth. mmm (2/m 2/m 2/m) : Pnna
16.12.13Wellsite(K,Ba,Ca,K2)Al2Si6O16 · 6H2OMon. 2/m : P21/m
16.12.14Merlinoite(K,Na)5(Ca,Ba)2Al9Si23O64 · 23H2OOrth.
16.12.15Anandite(Ba,K)(Fe2+,Mg)3((Si,Al,Fe)4O10)(S,OH)2Mon. 2/m : B2/b
16.12.16Fraipontite(Zn,Al)3((Si,Al)2O5)(OH)4Mon.
16.12.17SauconiteNa0.3Zn3((Si,Al)4O10)(OH)2 · 4H2OMon.
16.12.18Minehillite(K,Na)2-3Ca28Zn4Al4Si40O112(OH)16Hex.
16.12.19HendricksiteKZn3(Si3Al)O10(OH)2Mon. 2/m : B2/m
16.12.20Baileychlore(Zn,Fe2+,Al,Mg)6(Si,Al)4O10(OH)8Tric. 1

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 ParacelsianHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Tacconi, E. (1905) Di un silicato di alluminio e bario [paracelsian] dei calcefiri di Candoglia in valle del Toce. Rend. R. Istit. Lombardo Sci. Lett., Milano, 38, 636-643 (in Italian).
Mineralogical Magazine (1907): 14: 406 (abstract).
Spencer, L.J. (1942) Barium felspars (celsian and paracelsian) from Wales. Mineralogical Magazine, 26, 231-245.
Smith, J.V. (1953) The crystal structure of paracelsian, BaAl2Si2O8: Acta Crystallographica, 6, 613-620.
Deer, W.A., R.A. Howie, and J. Zussman (1963) Rock-forming Minerals, vol. 4, Framework Silicates, 166-178.
Lin, H.C., Foster, W.R. (1968): Studies in the system BaO–Al2O3–SiO2 I. The polymorphism of celsian. American Mineralogist 53, 134-144.
Chiari, G., G. Gazzoni, J.R. Craig, G.V. Gibbs, and S.J. Louisnathan (1985) Two independent refinements of the structure of paracelsian, BaAl2Si2O8: American Mineralogist: 70: 969-974.

Internet Links for ParacelsianHide

Localities for ParacelsianHide

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.
Italy (TL)
 
  • Piedmont
    • Verbano-Cusio-Ossola Province
      • Mergozzo
        • Candoglia
Tacconi, E. (1905): Di un silicato di alluminio e bario dei calcefiri di Candoglia in valle del Toce. Rendiconti del Regio Istituto Lombardo di Scienze e Lettere, Serie II, 38, 636-643.
Romania
 
  • Suceava
    • Suceava district
      • Iacobeni
http://minerals-of-the-carpathians.eu
UK
 
  • Wales
    • Gwynedd
      • Aberdaron
        • Rhiw
Spencer, L.J. (1942) Barium feldspars, (celsian and paracelsian) from Wales. Mineralogical Magazine, 26, 231-245.; Liferovich, R. P., Mitchell, R. H., Zozulya, D. R., & Shpachenko, A. K. (2006). Paragenesis and composition of banalsite, stronalsite, and their solid solution in nepheline syenite and ultramafic alkaline rocks. The Canadian Mineralogist, 44(4), 929-942.
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