Ekanite is an gem that is extemely rare. It was found in 1953 in the treasure gravels at Eheliyagoda, near Ratnapura, Sri Lanka. It’s also bought at Mt. Sainte Hilaire, Quebec, Canada. Ekanite may be strongly radioactive as defined in 49 CFR 173.403 (greater than 70 Bq/gram) due to the presence of Thorium (Th). Ekanite is almost always completely metamict. Metamictization is a procedure that is natural to radiation bombardment that benefits within the gradual and finally complete destruction of a mineral’s crystal lattice leaving the mineral amorphous. Ekanite is situated in shades of brown and green as are other metamict gems such as for example low Zircon and Sphene. 

Category: Silicate mineral
Chemical Formula: Ca2ThSi8O20
Calcium Thorium Silicate
Molecular Weight: 856.87 gm
Composition: Calcium 9.35 % Ca 13.09 % CaO
Thorium 27.08 % Th 30.81 % ThO2
Silicon 26.22 % Si 56.10 % SiO2
Oxygen 37.34 % O
  100.00 % 100.00 % = TOTAL OXIDE


Crystallography: Tetragonal – Trapezohedral (maybe metamict)
Crystal Habit: Poorly-formed pyramidal crystals, to 1 cm, as clusters of grains; rounded massive.
Twinning: None


Cleavage: Distinct on [101], indistinct on [001]
Fracture: Irregular, Uneven
Tenacity: Brittle
Moh’s Hardness: 5.0 – 6.5
Density: 3.28 – 3.32 (g/cm3)
Luminescence: None
Radioactivity: Strong; GRapi = 542,060.77 (Gamma Ray American Petroleum Institute Units)
Other: May be metamict due to radiation.


Color: Colorless, Yellow, Light to Dark Green, Brown, Red from inclusions
Transparency: Transparent to Translucent
Luster: Vitreous
Refractive Index: 1.590 – 1.596  Uniaxial ( – )
Birefringence: 0.0120
Dispersion: n/a
Pleochroism: n/a