Paracelsian
This page is currently not sponsored. Click here to sponsor this page.
About Paracelsian
Formula:
Ba(Al2Si2O8)
Colour:
Colourless to white, light yellow tint.
Lustre:
Vitreous
Hardness:
6
Crystal System:
Monoclinic
Member of:
Name:
From the Greek for "near" and "Celsian" in allusion to its relationship to that species.
Type Locality:
Polymorph of:
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.
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 Paracelsian
Approved, 'Grandfathered' (first described prior to 1959)
8/J.06-70
9.FA.40
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
76.1.5.1
76 : TECTOSILICATES Al-Si Framework
1 : Al-Si Framework with Al-Si frameworks
76 : TECTOSILICATES Al-Si Framework
1 : Al-Si Framework with Al-Si frameworks
16.12.5
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
Pronounciation of Paracelsian
Pronounciation:
Play | Recorded by | Country |
---|---|---|
Jolyon & Katya Ralph | United Kingdom |
Physical Properties of Paracelsian
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).
Poor cleavage {110} (unusual for feldspars).
Fracture:
Sub-Conchoidal
Optical Data of Paracelsian
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.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v
Chemical Properties of Paracelsian
Formula:
Ba(Al2Si2O8)
Elements listed:
Common Impurities:
Fe,Mg,Ca,Na,K,H2O
Crystallography of Paracelsian
Crystal System:
Monoclinic
Cell Parameters:
a = 9.07 Å, b = 9.58 Å, c = 8.57 Å
β = 90.01°
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 Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
---|---|---|---|---|---|---|---|
0000997 | Paracelsian | Chiari G, Gazzoni G, Craig J R, Gibbs G V, Louisnathan S J (1985) Two independent refinements of the structure of paracelsian, BaAl2Si2O8 American Mineralogist 70 969-974 | ![]() | 1985 | Benallt Mine, Carnarvonshire, U.K. | 0 | 293 |
0000998 | Paracelsian | Chiari G, Gazzoni G, Craig J R, Gibbs G V, Louisnathan S J (1985) Two independent refinements of the structure of paracelsian, BaAl2Si2O8 American Mineralogist 70 969-974 | ![]() | 1985 | Benallt Mine, Carnarvonshire, U.K. | 0 | 293 |
0009156 | Paracelsian | Smith J V (1953) The crystal structure of paracelsian, BaAl2Si2O8 Acta Crystallographica 6 613-620 | ![]() | 1953 | Benallt Mine, near Rhiw, Carnarvonshire, U.K. | 0 | 293 |
CIF Raw Data - click here to close
Type Occurrence of Paracelsian
Synonyms of Paracelsian
Ba Feldspar (in part)
Other Language Names for Paracelsian
Russian:Парацельзиан
Relationship of Paracelsian to other Species
Member of:
Other Members of this group:
Alkali Feldspar | A subgroup of the Feldspar Group, poor in calcium, and mostly rich in potassium. | |
Amazonite | K(AlSi3O8) | |
Andesine | (Na,Ca)[Al(Si,Al)Si2O8] | Tric. |
Anorthite | Ca(Al2Si2O8) | Tric. 1 : P1 |
Banalsite | Na2BaAl4Si4O16 | Orth. mm2 : Iba2 |
Buddingtonite | (NH4)(AlSi3O8) | Mon. 2 : P21 |
Bytownite | (Ca,Na)[Al(Al,Si)Si2O8] | Tric. |
Dmisteinbergite | Ca(Al2Si2O8) | Trig. 3 2 : P3 1 2 |
Ferrisanidine | K[Fe3+Si3O8] | Mon. 2/m : B2/m |
Filatovite | K(Al,Zn)2(As,Si)2O8 | Mon. 2/m |
Hexacelsian | BaAl2Si2O8 | Hex. 6/mmm (6/m 2/m 2/m) : P63/mcm |
Kokchetavite | K(AlSi3O8) | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
Kumdykolite | Na(AlSi3O8) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
Labradorite | (Ca,Na)[Al(Al,Si)Si2O8] | |
Oligoclase | (Na,Ca)[Al(Si,Al)Si2O8] | |
Reedmergnerite | NaBSi3O8 | Tric. |
Slawsonite | Sr(Al2Si2O8) | Mon. 2/m : P21/b |
Stronalsite | Na2SrAl4Si4O16 | Orth. |
Sunstone | A variety of feldspar (microcline or oligoclase, more rarely labradorite) that has schiller, ... | |
Svyatoslavite | Ca(Al2Si2O8) | Orth. |
Unnamed (New Ordered Member of the Alkali Feldspar Series) | KNa(Si6Al2)O16 | Mon. m |
Related Minerals - Nickel-Strunz Grouping
9.FA.05 | Kaliophilite | KAlSiO4 | Trig. 3 : P3 |
9.FA.05 | Kalsilite | KAlSiO4 | Hex. 6 2 2 : P63 2 2 |
9.FA.05 | Nepheline | Na3K(Al4Si4O16) | Hex. 6 : P63 |
9.FA.05 | Panunzite | (K,Na)AlSiO4 | Hex. 6 : P63 |
9.FA.05 | Trikalsilite | K2NaAl3(SiO4)3 | Hex. |
9.FA.05 | Yoshiokaite | (Ca,Na)[Al(Al,Si)O4] | Trig. 3 : P3 |
9.FA.05 | Megakalsilite | KAlSiO4 | Hex. 6 : P63 |
9.FA.10 | Malinkoite | NaBSiO4 | Hex. 6 : P63 |
9.FA.15 | Virgilite | LiAlSi2O6 | Hex. 6 2 2 : P62 2 2 |
9.FA.25 | Lisitsynite | KBSi2O6 | Orth. 2 2 2 : P2 2 2 |
9.FA.30 | Adularia | KAlSi3O8 | Mon. |
9.FA.30 | Anorthoclase | (Na,K)AlSi3O8 | Tric. |
9.FA.30 | Buddingtonite | (NH4)(AlSi3O8) | Mon. 2 : P21 |
9.FA.30 | Celsian | Ba(Al2Si2O8) | Mon. 2/m |
9.FA.30 | Hyalophane | (K,Ba)[Al(Si,Al)Si2O8] | Mon. |
9.FA.30 | Microcline | K(AlSi3O8) | Tric. 1 |
9.FA.30 | Orthoclase | K(AlSi3O8) | Mon. 2/m : B2/m |
9.FA.30 | Sanidine | K(AlSi3O8) | Mon. 2/m : B2/m |
9.FA.30 | Rubicline | Rb(AlSi3O8) | Tric. |
9.FA.30 | Monalbite | NaAlSi3O8 | Mon. 2/m : B2/m |
9.FA.35 | Albite | Na(AlSi3O8) | Tric. 1 |
9.FA.35 | Andesine | (Na,Ca)[Al(Si,Al)Si2O8] | Tric. |
9.FA.35 | Anorthite | Ca(Al2Si2O8) | Tric. 1 : P1 |
9.FA.35 | Bytownite | (Ca,Na)[Al(Al,Si)Si2O8] | Tric. |
9.FA.35 | Labradorite | (Ca,Na)[Al(Al,Si)Si2O8] | |
9.FA.35 | Oligoclase | (Na,Ca)[Al(Si,Al)Si2O8] | |
9.FA.35 | Reedmergnerite | NaBSi3O8 | Tric. |
9.FA.45 | Svyatoslavite | Ca(Al2Si2O8) | Orth. |
9.FA.45 | Kumdykolite | Na(AlSi3O8) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
9.FA.50 | Slawsonite | Sr(Al2Si2O8) | Mon. 2/m : P21/b |
9.FA.55 | Lisetite | CaNa2Al4Si4O16 | Orth. mm2 |
9.FA.60 | Banalsite | Na2BaAl4Si4O16 | Orth. mm2 : Iba2 |
9.FA.60 | Stronalsite | Na2SrAl4Si4O16 | Orth. |
9.FA.65 | Danburite | CaB2Si2O8 | Orth. mmm (2/m 2/m 2/m) |
9.FA.65 | Maleevite | BaB2Si2O8 | Orth. mmm (2/m 2/m 2/m) : Pnma |
9.FA.65 | Pekovite | SrB2Si2O8 | Orth. mmm (2/m 2/m 2/m) : Pnma |
9.FA.70 | Lingunite | (Na,Ca)AlSi3O8 | Tet. 4/m : I4/m |
9.FA.75 | Kokchetavite | K(AlSi3O8) | Hex. 6/mmm (6/m 2/m 2/m) : P6/mmm |
Related Minerals - Dana Grouping (8th Ed.)
76.1.5.2 | Slawsonite | Sr(Al2Si2O8) | Mon. 2/m : P21/b |
Related Minerals - Hey's Chemical Index of Minerals Grouping
16.12.1 | Stronalsite | Na2SrAl4Si4O16 | Orth. |
16.12.2 | Slawsonite | Sr(Al2Si2O8) | Mon. 2/m : P21/b |
16.12.3 | Brewsterite | Mon. | |
16.12.4 | Celsian | Ba(Al2Si2O8) | Mon. 2/m |
16.12.6 | Cymrite | BaAl2Si2(O,OH)8 · H2O | Mon. |
16.12.7 | Edingtonite | Ba[Al2Si3O10] · 4H2O | Orth. 2 2 2 : P21 21 21 |
16.12.8 | Banalsite | Na2BaAl4Si4O16 | Orth. mm2 : Iba2 |
16.12.9 | Harmotome | (Ba0.5,Ca0.5,K,Na)5[Al5Si11O32] · 12H2O | Mon. 2/m : P21/m |
16.12.10 | Hyalophane | (K,Ba)[Al(Si,Al)Si2O8] | Mon. |
16.12.11 | Balipholite | BaLiMg2Al3(Si2O6)2(OH)4 | Orth. |
16.12.12 | Armenite | BaCa2Al6Si9O30 · 2H2O | Orth. mmm (2/m 2/m 2/m) : Pnna |
16.12.13 | Wellsite | (K,Ba,Ca,K2)Al2Si6O16 · 6H2O | Mon. 2/m : P21/m |
16.12.14 | Merlinoite | (K,Na)5(Ca,Ba)2Al9Si23O64 · 23H2O | Orth. |
16.12.15 | Anandite | (Ba,K)(Fe2+,Mg)3((Si,Al,Fe)4O10)(S,OH)2 | Mon. 2/m : B2/b |
16.12.16 | Fraipontite | (Zn,Al)3((Si,Al)2O5)(OH)4 | Mon. |
16.12.17 | Sauconite | Na0.3Zn3((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
16.12.18 | Minehillite | (K,Na)2-3Ca28Zn4Al4Si40O112(OH)16 | Hex. |
16.12.19 | Hendricksite | KZn3(Si3Al)O10(OH)2 | Mon. 2/m : B2/m |
16.12.20 | Baileychlore | (Zn,Fe2+,Al,Mg)6(Si,Al)4O10(OH)8 | Tric. 1 |
Other Information
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 Paracelsian
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 Paracelsian
mindat.org URL:
https://www.mindat.org/min-3082.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
Localities for Paracelsian
Locality List




All localities listed without proper references should be considered as questionable.
Italy (TL) | |
| 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 | |
| http://minerals-of-the-carpathians.eu |
UK | |
| 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. |
Benallt Mine, Rhiw, Aberdaron, Gwynedd, Wales, UK