Ekanite

Chemistry: Metamict-Calcium thorium silicate
Crystal system: Amorphous from Tetragonal; usually micro crystals; rarely large.
Color: Transparent to translucent; metamict: green, yellow, light brown; crystalline: yellow-red; phenomena: may show 4-rayed star.
Hardness: 6.0 – 6.5
Cleavage: -
Specific gravity: 3.28
Refractive index: 1.597 metamict; SR.
Luster: Vitreous.
Dispersion: -
Dichroism: -
Occurrence: Gem gravels of Sri Lanka; some crystalline material found in Canada.

Notes
Found in 1953; mildly radioactive; may be cut as collector’s stone.