Most Ekanite comes from Sri Lanka, but deposits have also been found in Canada and Russia. Gem quality Ekanite is relatively uncommon. As a rule, Ekanite gemstones are green but there are also yellow and red varieties.

Chemically, it is ThCa2Si8O20 by weight, approximately 30% thorium). On the Moh's hardness scale it ranks 6 to 6.5.

The rather noticeable radioactivity of the stone is due to its thorium content. Over time, the Ekanite will deteriorate as a result of the damage caused to the crystalline lattice by the alpha emissions.

Size: 5.1 x 4.5 mm

Weight: 0.12 grams; 0.6 ct.


  • 3,000 pCi (100 Bq) of Th-232 with all the members of the decay series in secular equilibrium
  • 1,200 cpm above background with a pancake GM