Much the best practical source of helium is thorianite, a mineral imported from Ceylon for the manufacture of thoria.
It may be obtained as jet black octahedra (isomorphous with thoria) by fusion with borax.
The name thoria (after the Scandinavian god Thor) was first given in 1815 by Berzelius to a supposed new earth which he had extracted from several rare Swedish minerals.
In 1828 he gave the name thoria to an earth which he extracted from a mineral found at Lerdn.
Thorium chloride, ThC1 4, is obtained as white shining crystals by heating a mixture of carbon and thoria in a current of chlorine.