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Ekanite

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Formula:
Ca2ThSi8O20
Colour:
Green in various shades, straw-yellow, dark red, colorles
Lustre:
Vitreous
Hardness:
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.
See also the related Steacyite Group.

Visit gemdat.org for gemological information about Ekanite.


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Classification of EkaniteHide

Approved
First Published:
1961
9.EA.10

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
14.16.16

14 : Silicates not Containing Aluminum
16 : Silicates of U

Pronounciation of EkaniteHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of EkaniteHide

Vitreous
Colour:
Green in various shades, straw-yellow, dark red, colorles
Streak:
White
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
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 EkaniteHide

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 EkaniteHide

Formula:
Ca2ThSi8O20
Common Impurities:
U,Fe,Pb,Al,Mn,Pb,Mg

Crystallography of EkaniteHide

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 DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
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 EkaniteHide

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.
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 EkaniteHide

German:Ekanit
Russian:Эканит
Simplified Chinese:硅钙铀钍矿
Spanish:Ekanita
Traditional Chinese:矽鈣鈾釷礦

Common AssociatesHide

Associated Minerals Based on Photo Data:
Diopside1 photo of Ekanite associated with Diopside on mindat.org.
Wollastonite1 photo of Ekanite associated with Wollastonite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.EA.05CuprorivaiteCaCuSi4O10Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc
9.EA.05GillespiteBaFe2+Si4O10Tet.
9.EA.05EffenbergeriteBaCuSi4O10Tet. 4/mmm (4/m 2/m 2/m) : P4/ncc
9.EA.05WesselsiteSrCuSi4O10Tet.
9.EA.15Fluorapophyllite-(K)KCa4(Si8O20)(F,OH) · 8H2OTet. 4/mmm (4/m 2/m 2/m) : P4/mnc
9.EA.15Hydroxyapophyllite-(K)KCa4(Si8O20)(OH,F) · 8H2OTet.
9.EA.15Fluorapophyllite-(Na)NaCa4(Si8O20)F · 8H2OOrth.
9.EA.20MagadiiteNa2Si14O29 · 11H2OMon.
9.EA.25DalyiteK2ZrSi6O15Tric.
9.EA.25DavaniteK2TiSi6O15Tric.
9.EA.30Sazhinite-(Ce)Na2CeSi6O14•6H2O
9.EA.30Sazhinite-(La)Na3La[Si6O15] · 2H2OOrth. mm2 : Pmm2
9.EA.35ArmstrongiteCaZr[Si6O15] · 3H2OMon.
9.EA.40OkeniteCa10Si18O46 · 18H2OTric. 1 : P1
9.EA.45NekoiteCa3Si6O15·7H2OTric. 1 : P1
9.EA.50CavansiteCa(VO)Si4O10 · 4H2OOrth. mmm (2/m 2/m 2/m)
9.EA.55PentagoniteCa(VO)Si4O10 · 4H2OOrth. mm2
9.EA.60PenkvilksiteNa4Ti2Si8O22 · 4H2OOrth. mmm (2/m 2/m 2/m) : Pbcn
9.EA.60TumchaiteNa2Zr(Si4O11) · 2H2OMon.
9.EA.65NabesiteNa2BeSi4O10 · 4H2OOrth. 2 2 2 : P21 21 21
9.EA.70Ajoite(K,Na)Cu7AlSi9O24(OH)6 · 3H2OTric.
9.EA.75ZeravshaniteNa2Cs4Zr3[Si18O45]*2H2OMon. 2/m : B2/b
9.EA.80Bussyite-(Ce)(Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4Mon. 2/m : B2/b
9.EA.85PlumbophyllitePb2Si4O10 · H2OOrth. mmm (2/m 2/m 2/m) : Pbcn

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

14.16.1UranosiliteUO3 · 7SiO2Orth.
14.16.2Coffinite(U4+,Th)(SiO4)1-x(OH)4xTet.
14.16.3Soddyite(UO2)2SiO4 · 2H2OOrth.
14.16.4Swamboite-(Nd)Nd0.333[(UO2)(SiO3OH)](H2O)∼2.5Mon.
14.16.5WeeksiteK2(UO2)2(Si5O13) · 4H2OOrth.
14.16.6Boltwoodite(K,Na)(UO2)(SiO3OH) · 1.5H2OMon. 2 : P21
14.16.7NatroboltwooditeNa(UO2)(SiO3OH) · H2O
14.16.8CuprosklodowskiteCu(UO2)2(SiO3OH]2 · 6H2OTric. 1 : P1
14.16.9SklodowskiteMg(UO2)2(SiO3OH)2 · 6H2OMon. 2/m : B2/m
14.16.10UranophaneCa(UO2)2(SiO3OH)2 · 5H2OMon. 2 : P21
14.16.11Uranophane-βCa(UO2)2(SiO3OH)2 · 5H2OMon.
14.16.12HaiweeiteCa(UO2)2[Si5O12(OH)2] · 6H2OMon.
14.16.13MetahaiweeiteCa(UO2)2Si6O15 · nH2O
14.16.15SteacyiteK0.3(Na,Ca)2ThSi8O20Tet. 4/mmm (4/m 2/m 2/m) : P4/mcc
14.16.17KasolitePb(UO2)[SiO4] · H2OMon. 2/m : P21/b
14.16.18OrlitePb3(UO2)3(Si2O7)2 · 6H2O
14.16.19OursiniteCo(UO2)2(SiO3OH)2 · 6H2OOrth. mmm (2/m 2/m 2/m) : Cmca

Other InformationHide

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 EkaniteHide

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.

Internet Links for EkaniteHide

Localities for EkaniteHide

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.
Canada
 
  • Québec
    • Abitibi-Témiscamingue
      • Témiscamingue RCM
        • Les Lacs-du-Témiscamingue
GSC database: XRD only; metamict
    • Montérégie
      • La Vallée-du-Richelieu RCM
        • Mont Saint-Hilaire
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.
  • Yukon
    • Dawson Mining District
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
 
  • Baden-Württemberg
    • Black Forest
      • Waldshut
        • Detzeln
Hess, E., Graeser, S. & Gabriel, W. (2011): Das Porphyrwerk Detzeln im Steinatal und seine Mineralien. Lapis 36 (4), 25-35; 54.
Italy
 
  • Campania
    • Naples Province
      • Somma-Vesuvius Complex
        • Monte Somma
          • Ercolano
            • San Vito
Russo, M., Campostrini, I., Demartin, F. (2013). Nuove specie minerali al Monte Somma: V. L'ekanite. Micro, 3/2013, 142-144
  • Latium
    • Rome Province
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.
        • Albano Laziale
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.
      • Rome
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
    • Viterbo Province
      • Vico Lake
No reference listed
  • Lombardy
    • Sondrio Province
      • Valtellina
Lapis, 19 (10), 15-21+86.
  • Tuscany
    • Grosseto Province
      • Pitigliano
Liotti L., 1991. I minerali dei vulcani laziali a Pitigliano (Grosseto). Riv. Mineral. Ital., 15: 121-139.
    • Livorno Province
      • Campigliese (Campiglia Mountains; Campiglia Ridge)
        • Campiglia Marittima
Biagioni, C. (2016) Ekanite. Nuovi ritrovamenti a Botro ai Marmi, Campiglia Marittima (LI). Rivista Mineralogica Italiana, 40, 242-245.
Myanmar
 
  • Mandalay Region (Mandalay Division)
    • Pyin-Oo-Lwin District
      • Mogok Township
        • Mogok Valley
Pavel M. Kartashov analytical data, Sieghard Ellenberger specimens
Portugal
 
  • Azores District
    • São Miguel Island
      • Água de Pau Massif
Samples collected by Luigi Chiappino and analysed by Dr. Anthony Kampf, Natural History Museum of Los Angeles County, USA
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
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.
      • Ratnapura
Nature 190 (1961), 997
  • Uva Province
    • Moneragala District
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.: Neoproterozoic amorphous “ekanite” (Ca2Th0.9U0.1Si8O20) from Okkampitiya, Sri Lanka: A metamict gemstone with excellent lead-retention performance. Geology, 45, 919–922.
USA
 
  • California
    • Tulare Co.
      • Dumtah
Mineralogical Record: 34(2): 159-166
Mineral and/or Locality  
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