Ekanite
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About Ekanite
Formula:
Ca2ThSi8O20
Colour:
Green in various shades, straw-yellow, dark red, colourless
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.95 - 3.28
Crystal System:
Tetragonal
Name:
Named in honor of Mr. F. L. D. Ekanayake (Colombo, Sri Lanka), a gemmologist, who first suspected specimens were a new mineral.
Classification of Ekanite
Approved
First Published:
1961
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
Pronounciation of Ekanite
Pronounciation:
Play | Recorded by | Country |
---|---|---|
Jolyon & Katya Ralph | United Kingdom |
Physical Properties of Ekanite
Vitreous
Colour:
Green in various shades, straw-yellow, dark red, colourless
Streak:
White
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Distinct on {101}, indistinct on {001}
Distinct on {101}, indistinct on {001}
Fracture:
Irregular/Uneven
Density:
2.95 - 3.28 g/cm3 (Measured) 3.36 g/cm3 (Calculated)
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.
and does not take into account mineral colouration.
Surface Relief:
Low
Chemical Properties of Ekanite
Formula:
Ca2ThSi8O20
Elements listed:
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 V:
833.94 ų (Calculated from Unit Cell)
Z:
2
Comment:
Very often metamict.
X-Ray Powder Diffraction
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
Place of Conservation of Type Material:
Canadian Geological Survey, Ottawa, Canada, 62722.
The Natural History Museum, London, England, 1961, 472.
National Museum of Natural History, Washington, D.C., USA, 148771.
The Natural History Museum, London, England, 1961, 472.
National Museum of Natural History, Washington, D.C., USA, 148771.
Reference:
Anderson, B.W., Claringbull, G.F., Davis, R.J., Hill, D.K. (1961) Ekanite, a new metamict mineral from Ceylon. Nature: 190: 997.
Other Language Names for Ekanite
Common Associates
Associated Minerals Based on Photo Data:
Diopside | 1 photo of Ekanite associated with Diopside on mindat.org. |
Wollastonite | 1 photo of Ekanite associated with Wollastonite on mindat.org. |
Related Minerals - Nickel-Strunz Grouping
9.EA.05 | Cuprorivaite | CaCuSi4O10 | Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc |
9.EA.05 | Gillespite | BaFe2+Si4O10 | Tet. |
9.EA.05 | Effenbergerite | BaCuSi4O10 | Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc |
9.EA.05 | Wesselsite | SrCuSi4O10 | Tet. |
9.EA.15 | Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O | Tet. 4/mmm (4/m 2/m 2/m) : P4/mnc |
9.EA.15 | Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O | Tet. |
9.EA.15 | Fluorapophyllite-(Na) | NaCa4(Si8O20)F · 8H2O | Orth. |
9.EA.20 | Magadiite | Na2Si14O29 · 11H2O | Mon. |
9.EA.25 | Dalyite | K2ZrSi6O15 | Tric. |
9.EA.25 | Davanite | K2TiSi6O15 | Tric. |
9.EA.30 | Sazhinite-(Ce) | Na2CeSi6O14•6H2O | |
9.EA.30 | Sazhinite-(La) | Na3La[Si6O15] · 2H2O | Orth. mm2 : Pmm2 |
9.EA.35 | Armstrongite | CaZr[Si6O15] · 3H2O | Mon. |
9.EA.40 | Okenite | Ca10Si18O46 · 18H2O | Tric. 1 : P1 |
9.EA.45 | Nekoite | Ca3Si6O15·7H2O | Tric. 1 : P1 |
9.EA.50 | Cavansite | Ca(VO)Si4O10 · 4H2O | Orth. mmm (2/m 2/m 2/m) |
9.EA.55 | Pentagonite | Ca(VO)Si4O10 · 4H2O | Orth. mm2 |
9.EA.60 | Penkvilksite | Na4Ti2Si8O22 · 4H2O | Orth. mmm (2/m 2/m 2/m) : Pbcn |
9.EA.60 | Tumchaite | Na2Zr(Si4O11) · 2H2O | Mon. |
9.EA.65 | Nabesite | Na2BeSi4O10 · 4H2O | Orth. 2 2 2 : P21 21 21 |
9.EA.70 | Ajoite | (K,Na)Cu7AlSi9O24(OH)6 · 3H2O | Tric. |
9.EA.75 | Zeravshanite | Na2Cs4Zr3[Si18O45]*2H2O | Mon. 2/m : B2/b |
9.EA.80 | Bussyite-(Ce) | (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 | Mon. 2/m : B2/b |
9.EA.85 | Plumbophyllite | Pb2Si4O10 · H2O | Orth. mmm (2/m 2/m 2/m) : Pbcn |
Related Minerals - Hey's Chemical Index of Minerals Grouping
14.16.1 | Uranosilite | UO3 · 7SiO2 | Orth. |
14.16.2 | Coffinite | U(SiO4) · nH2O | Tet. |
14.16.3 | Soddyite | (UO2)2SiO4 · 2H2O | Orth. |
14.16.4 | Swamboite-(Nd) | Nd0.333[(UO2)(SiO3OH)](H2O)∼2.5 | Mon. |
14.16.5 | Weeksite | K2(UO2)2(Si5O13) · 4H2O | Orth. |
14.16.6 | Boltwoodite | (K,Na)(UO2)(SiO3OH) · 1.5H2O | Mon. 2 : P21 |
14.16.7 | Natroboltwoodite | Na(UO2)(SiO3OH) · H2O | |
14.16.8 | Cuprosklodowskite | Cu(UO2)2(SiO3OH]2 · 6H2O | Tric. 1 : P1 |
14.16.9 | Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O | Mon. 2/m : B2/m |
14.16.10 | Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O | Mon. 2 : P21 |
14.16.11 | Uranophane-β | Ca(UO2)2(SiO3OH)2 · 5H2O | Mon. 2/m : P21/b |
14.16.12 | Haiweeite | Ca(UO2)2[Si5O12(OH)2] · 6H2O | Mon. |
14.16.13 | Metahaiweeite | Ca(UO2)2Si6O15 · nH2O | |
14.16.15 | Steacyite | K0.3(Na,Ca)2ThSi8O20 | Tet. 4/mmm (4/m 2/m 2/m) : P4/mcc |
14.16.17 | Kasolite | Pb(UO2)[SiO4] · H2O | Mon. 2/m : P21/b |
14.16.18 | Orlite | Pb3(UO2)3(Si2O7)2 · 6H2O | |
14.16.19 | Oursinite | Co(UO2)2(SiO3OH)2 · 6H2O | Orth. mmm (2/m 2/m 2/m) : Cmca |
Other Information
Notes:
Radioactive
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:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Anderson, B.W., Claringbull, G.F., Davis, R.J., Hill, D.K. (1961) Ekanite, a new metamict mineral from Ceylon. Nature: 190: 997.
Fleischer, M. (1961) New mineral names. American Mineralogist: 46: 1513-1520.
Gübelin, E.J. (1962) Ekanite. The Gemmologist: 31(373): 142-152.
Gübelin, E.J. (1962) Ekanite. The Gemmologist: 31(374): 165-169.
International Mineralogical Association (1967) Commission on new minerals and mineral names. Mineralogical Magazine: 36: 131-136.
Chromy, B. (1973) The wee crystals. Earth Science: 1973: 227-278. [see http://www.mindat.org/mesg-6-367561.html]
Perrault, G., Richard, P. (1973) L'ekanite de Saint-Hilaire, P.Q.. The 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.
Dunn, P.J., Fleischer, M., Burns, R.G., Pabst, A. (1983) New mineral names. American Mineralogist: 68: 471-475.
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.
Evans, R.J., Groat, L.A. (2012) Structure and topology of dumortierite and dumortierite-like materials. The Canadian Mineralogist: 50: 1197-1231.
Nasdala, L., Corfu, F., Blaimauer, D., Chanmuang, C., Ruschel, K., Škoda, R., Wildner, M., Wirth, R., Zeug, M. & Zoysa, E.G. (2017): Neoproterozoic amorphous “ekanite” (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance. Geology, 45, 919–922. [https://doi.org/10.1130/G39334.1]
Internet Links for Ekanite
mindat.org URL:
https://www.mindat.org/min-1361.html
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Localities for Ekanite
Locality List




All localities listed without proper references should be considered as questionable.
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. |
Kyrgyzstan | |
| Pautov, L. A., Karpenko, V. Y., & Agakhanov, A. A. (2013) Baratovite-katayamalite Minerals from the Hodzha-achkan Alcaline Massif (Kirgizia). New Data on Minerals. 48:12-36 |
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; Nasdala, L., Corfu, F., Blaimauer, D., Chanmuang, C., Ruschel, K., Škoda, R., Wildner, M., Wirth, R., Zeug, M. & Zoysa, E.G. (2017): Neoproterozoic amorphous “ekanite” (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance. Geology, 45, 919–922. |
USA | |
| Mineralogical Record: 34(2): 159-166 |
Case Collina, Pitigliano, Grosseto Province, Tuscany, Italy