Assertion: thorium | /r/HasProperty | rare
Facets:
value: very
type: DEGREE
Source sentences:
text: THORIUM used as a noun is very rare.
text: Thorium is a rare resource that can only be mined with a laser drill or an airblast drill.
text: Separation is more difficult if the fission products are mixed with thorium, because thorium, plutonium and the lanthanides (rare earth elements) are chemically similar.
text: Thorium, at atomic number 90, is one of the rarest elements.