Ekanite

Big Photo

Sri Lanka
3.51 carats
© Rarestone.com

Ekanite is named in 1961 after F.L.D. Ekanayake, discoverer of the mineral in 1953 in Sri Lanka. The material was dark, dull green, but when it was polished as cabochons it revealed a four-rayed star. The specimen was found to be metamict and radioactive.

Ekanite occurs in poorly formed prismatic crystals of straw-yellow colour when pure, sometimes dark red or brown colour, which is caused by inclusions.

Radioactivity limits the use of Ekanite as a gemstone, all specimens should be stored with great care. Cut stones have weight up to 25 carats.

Ekanite Gemstones by Colour

This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
 
 
 

Ekanite Gemstones by Size

This table shows distribution of Ekanite gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:0.38 cts
Heaviest:3.51 cts
Average:1.41 cts
Total photos:4
Do you have a larger Ekanite? Why not upload a photo?
0.38ct to 0.69ct0.69ct to 1.01ct1.01ct to 1.32ct1.32ct to 1.63ct1.63ct to 1.95ct1.95ct to 2.26ct2.26ct to 2.57ct2.57ct to 2.88ct2.88ct to 3.20ct3.20ct to 3.51ct
General Information
Chemical Formula
ThCa
 
2
Si
 
8
O
 
20
Walter Schumann, Gemstones of the world (2001)
More from other references
Photos of natural/un-cut material from mindat.org
Physical Properties of Ekanite
Mohs Hardness6 to 6.5
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Specific Gravity3.28 to 3.32
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Cleavage QualityDistinct
Arthur Thomas, Gemstones (2009)
FractureUneven
Arthur Thomas, Gemstones (2009)
Optical Properties of Ekanite
Refractive Index1.593 to 1.596
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
More from other references
Optical CharacterUniaxial/-
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Birefringence0.001
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
Chatoyancy(Rare) star 4
Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010)
Colour
Colour (General)Green, yellow-green, brownish
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
TransparencyTransparent,Translucent
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
More from other references
LustreVitreous
Walter Schumann, Gemstones of the world (2001)
More from other references
Crystallography of Ekanite
Crystal SystemTetragonal
Walter Schumann, Gemstones of the world (2001) Originally tetragonal, later amorphous, due to persisting radioactivity.More from other references
HabitPoorly formed prismatic crystals
Michael O’Donoghue, Gems, Sixth Edition (2006)
More from other references
Geological Environment
Where found:Skarn (?), placer deposits
E. Ya. Kievlenko, Geology of gems (2003)
Spectrographic Data
Calculated Spectra:
Click spectra for more information
Ekanite - Locality: Sri Lanka
Inclusions in Ekanite
Black thorite crystals with radiation halos - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5
Further Information
Mineral information:Ekanite information at mindat.org
Significant Gem Localities
Canada
 
  • Yukon
    • Dawson mining district
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 407
Myanmar
 
  • Mandalay Region
    • Pyin-Oo-Lwin District
Sri Lanka
 
  • Sabaragamuwa Province
    • Ratnapura District
      • Ratnapura
Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 407
Copyright © Jolyon & Katya Ralph 1993-2019. Site Map. Locality, gem & photograph data are the copyright of the individuals who submitted them. For more information please contact the . Gemdat.org is an online information resource dedicated to providing free gemmological information to all.