Assertion: plutonium | /r/AtLocation | trace amounts
Facets:
value: in nature
type: LOCATION
Source sentences:
text: In nature, plutonium is relatively rare, occurring in uranium rich ores in trace amounts; most of the world's working supply of this element is obtained through neutron bombardment of uranium, a close neighbor on the periodic table.
text: Plutonium occurs only in trace amounts in nature.