Ekanite
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Formula:
Ca2ThSi8O20
System:
Tetragonal
Colour:
Green in various shades, ...
Hardness:
4½
Classification of Ekanite
Approved
8/E.10-10
9.EA.10
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
72.1.1.1
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
1 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
1 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with 4-membered rings
14.16.16
14 : Silicates not Containing Aluminum
16 : Silicates of U
14 : Silicates not Containing Aluminum
16 : Silicates of U
Physical Properties of Ekanite
Colour:
Green in various shades, straw-yellow, dark red
Hardness (Mohs):
4½
Optical Data of Ekanite
Type:
Uniaxial (-)
RI values:
nω = 1.580 nε = 1.568
Max Birefringence:
δ = 0.012
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Low
Chemical Properties of Ekanite
Formula:
Ca2ThSi8O20
Elements listed in formula:
Common Impurities:
U,Fe,Pb,Al,Mn,Pb,Mg
Crystallography of Ekanite
Crystal System:
Tetragonal
Class (H-M):
4 2 2 - Trapezohedral
Space Group:
I4 2 2
Cell Parameters:
a = 7.483(3) Å, c = 14.893(6) Å
Ratio:
a:c = 1 : 1.99
Unit Cell Volume:
V 833.94 ų (Calculated from Unit Cell)
Z:
2
Comment:
Very often metamict.
X-Ray Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.45 | (58) |
| 6.70 | (61) |
| 4.14 | (100) |
| 3.343 | (96) |
| 3.265 | (65) |
| 2.642 | (54) |
| 1.796 | (26) |
Comments:
Very often metamict.
Type Occurrence of Ekanite
Relationship of Ekanite to other Species
| 9.EA.05 | Cuprorivaite | CaCuSi4O10 |
| 9.EA.05 | Gillespite | BaFe2+Si4O10 |
| 9.EA.05 | Effenbergerite | BaCuSi4O10 |
| 9.EA.05 | Wesselsite | SrCuSi4O10 |
| 9.EA.15 | Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O |
| 9.EA.15 | Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O |
| 9.EA.15 | Fluorapophyllite-(Na) | NaCa4(Si8O20)F · 8H2O |
| 9.EA.20 | Magadiite | Na2Si14O29 · 11H2O |
| 9.EA.25 | Dalyite | K2ZrSi6O15 |
| 9.EA.25 | Davanite | K2TiSi6O15 |
| 9.EA.30 | Sazhinite-(Ce) | Na2CeSi6O14•6H2O |
| 9.EA.30 | Sazhinite-(La) | Na3La[Si6O15] · 2H2O |
| 9.EA.35 | Armstrongite | CaZr[Si6O15] · 3H2O |
| 9.EA.40 | Okenite | Ca10Si18O46 · 18H2O |
| 9.EA.45 | Nekoite | Ca3Si6O15·7H2O |
| 9.EA.50 | Cavansite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.55 | Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.60 | Penkvilksite | Na4Ti2Si8O22 · 4H2O |
| 9.EA.60 | Tumchaite | Na2Zr(Si4O11) · 2H2O |
| 9.EA.65 | Nabesite | Na2BeSi4O10 · 4H2O |
| 9.EA.70 | Ajoite | (K,Na)Cu7AlSi9O24(OH)6 · 3H2O |
| 9.EA.75 | Zeravshanite | Na2Cs4Zr3[Si18O45]*2H2O |
| 9.EA.80 | Bussyite-(Ce) | (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 |
| 9.EA.85 | Plumbophyllite | Pb2Si4O10 · H2O |
| 14.16.1 | Uranosilite | UO3 · 7SiO2 |
| 14.16.2 | Coffinite | (U4+,Th)(SiO4)1-x(OH)4x |
| 14.16.3 | Soddyite | (UO2)2SiO4 · 2H2O |
| 14.16.4 | Swamboite-(Nd) | Nd0.333[(UO2)(SiO3OH)](H2O)∼2.5 |
| 14.16.5 | Weeksite | K2(UO2)2(Si5O13) · 4H2O |
| 14.16.6 | Boltwoodite | (K,Na)(UO2)(SiO3OH) · 1.5H2O |
| 14.16.7 | Natroboltwoodite | Na(UO2)(SiO3OH) · H2O |
| 14.16.8 | Cuprosklodowskite | Cu(UO2)2(SiO3OH]2 · 6H2O |
| 14.16.9 | Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 14.16.10 | Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 14.16.11 | Uranophane-β | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 14.16.12 | Haiweeite | Ca(UO2)2[Si5O12(OH)2] · 6H2O |
| 14.16.13 | Metahaiweeite | Ca(UO2)2Si6O15 · nH2O |
| 14.16.15 | Steacyite | K0.3(Na,Ca)2ThSi8O20 |
| 14.16.17 | Kasolite | Pb(UO2)[SiO4] · H2O |
| 14.16.18 | Orlite | Pb3(UO2)3(Si2O7)2 · 6H2O |
| 14.16.19 | Oursinite | Co(UO2)2(SiO3OH)2 · 6H2O |
Other Names for Ekanite
Name in Other Languages:
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 Ekanite
Reference List:
ANDERSON, B.W., CLARINGBULL, G.F., DAVIS, R.J. & HILL, D.K. (1961): Ekanite, a new metamict mineral from Ceylon. Nature 190, 997.
GÜBELIN, E.J. (1962) Ekanite. The Gemmologist, 31(No. 373), 142-152, (No. 374),165-169.
Chromy, B. (1973): The wee crystals. Earth Science, 1973, 227-278. [see http://www.mindat.org/mesg-6-367561.html]
SZYMAŃSKI, J.T., OWENS, D.R., ROBERTS, A.C., ANSELL, H.G. & CHAO, G.Y. (1982): A mineralogical study and crystal structure determination of nonmetamict ekanite ThCa2Si8O20. Canadian Mineralogist 20, 65 75.
PERRAULT, G. & SZYMAŃSKI, J.T. (1982): Steacyite, a new name and a re evaluation of the nomenclature of "ekanite" group minerals. Canadian Mineralogist 20, 59 63.
Della Ventura, G., Maras, A. & Parodi, G. C. (1986): Nonmetamict U-rich ekanite from Pitigliano (Tuscany, Italy). Atti della Accademia Nazionale dei Lincei, Rendiconti, Classe di Scienze Fisiche, Matematiche e Naturali 80, 585-592.
GÜBELIN, E.J. (1962) Ekanite. The Gemmologist, 31(No. 373), 142-152, (No. 374),165-169.
Chromy, B. (1973): The wee crystals. Earth Science, 1973, 227-278. [see http://www.mindat.org/mesg-6-367561.html]
SZYMAŃSKI, J.T., OWENS, D.R., ROBERTS, A.C., ANSELL, H.G. & CHAO, G.Y. (1982): A mineralogical study and crystal structure determination of nonmetamict ekanite ThCa2Si8O20. Canadian Mineralogist 20, 65 75.
PERRAULT, G. & SZYMAŃSKI, J.T. (1982): Steacyite, a new name and a re evaluation of the nomenclature of "ekanite" group minerals. Canadian Mineralogist 20, 59 63.
Della Ventura, G., Maras, A. & Parodi, G. C. (1986): Nonmetamict U-rich ekanite from Pitigliano (Tuscany, Italy). Atti della Accademia Nazionale dei Lincei, Rendiconti, Classe di Scienze Fisiche, Matematiche e Naturali 80, 585-592.
Internet Links for Ekanite
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https://www.mindat.org/min-1361.html
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Specimens:
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Localities for Ekanite
This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the 
symbol to view information about a locality.
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(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? 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 | |
| GSC database: XRD only; metamict |
| Richard A.J. (1971), La methode d'addition symbolique et la definition de la structure cristalline de l'ekanite de St-Hilaire, P.Q. Ph.D. Thesis, Ecole polytechnique de Montréal, Canada; Perrault G. and Richard P. (1973), L'ekanite de St-Hilaire, P.Q. Canadian Mineralogist: 11: 913-929. |
| SZYMAŃSKI, J.T., OWENS, D.R., ROBERTS, A.C., ANSELL, H.G. & CHAO, G.Y. (1982): A mineralogical study and crystal structure determination of nonmetamict ekanite ThCa2Si8O20. Canadian Mineralogist 20, 65-75. PERRAULT, G. & SZYMAŃSKI, J.T. (1982): Steacyite, a new name and a re evaluation of the nomenclature of "ekanite" group minerals. Canadian Mineralogist 20, 59 63. |
| SZYMAŃSKI, J.T., OWENS, D.R., ROBERTS, A.C., ANSELL, H.G. & CHAO, G.Y. (1982): A mineralogical study and crystal structure determination of nonmetamict ekanite ThCa2Si8O20. Canadian Mineralogist 20, 65 75. | |
Germany | |
| Hess, E., Graeser, S. & Gabriel, W. (2011): Das Porphyrwerk Detzeln im Steinatal und seine Mineralien. Lapis 36 (4), 25-35; 54. |
Italy | |
| Russo, M., Campostrini, I., Demartin, F. (2013). Nuove specie minerali al Monte Somma: V. L'ekanite. Micro, 3/2013, 142-144 |
| Caponera, I., Fiori, S., Pucci, R., & Signoretti, E. (2007). I minerali dei Colli Albani. Un aggiornamento sugli ultimi dieci anni di ricerche. Rivista Mineralogica Italiana, 31 (2), 74-91. |
| Gianfagna, A., Merlino, S., Perchiazzi, N. (1988). Guarinite, a new finding in the sanidinite ejecta of the IV Hydromagmatic Unit from Albano lake crater, Latium, Italy. Periodico di Mineralogia, 57: 81-84. |
| Gresta, S., Duronio, F., Mancinella D. (2002): Geositi e Sistema delle Aree Protette del Lazio: idee per la geoconservazione. Il Cercapietre. Not. del Gruppo Mineralogico Romano, 1-2: 48-55 |
| No reference listed |
| Lapis, 19 (10), 15-21+86. |
| Liotti L., 1991. I minerali dei vulcani laziali a Pitigliano (Grosseto). Riv. Mineral. Ital., 15: 121-139. |
| Biagioni, C. (2016) Ekanite. Nuovi ritrovamenti a Botro ai Marmi, Campiglia Marittima (LI). Rivista Mineralogica Italiana, 40, 242-245. |
Myanmar | |
| Pavel M. Kartashov analytical data, Sieghard Ellenberger specimens |
Portugal | |
| Samples collected by Luigi Chiappino and analysed by Dr. Anthony Kampf, Natural History Museum of Los Angeles County, USA |
Sri Lanka | |
| Dissanayake, C. B., Chandrajith, R. O. H. A. N. A., & Tobschall, H. J. (2000). The geology, mineralogy and rare element geochemistry of the gem deposits of Sri Lanka. BULLETIN-GEOLOGICAL SOCIETY OF FINLAND, 72(1/2), 5-20. |
| Nature 190 (1961), 997 |
| Dr. Jaroslav Hyrsl specimens; Mathavan, V., Kalubandara, S. T., & Fernando, G. W. A. R. (2000). Occurrences of two new types of gem deposits in Okkampitiya gem field in Sri Lanka. |
USA | |
| Mineralogical Record: 34(2): 159-166 |
Case Collina, Pitigliano, Grosseto Province, Tuscany, Italy