![thorite thorite](https://www.tekportal.net/wp-content/uploads/2018/11/thorite.jpg)
noun
- a rare mineral, thorium silicate, ThSiO4, occurring in the form of yellow or black crystals.
noun
- a yellow, brownish, or black radioactive mineral consisting of tetragonal thorium silicate. It occurs in coarse granite and is a source of thorium. Formula: ThSiO 4