Crossword clue: a rare metallic element of uncertain properties and identity, said to have been found in the mineral gadolinite.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
a soft silvery metallic element of the rare earth group; isotope 170 emits X-rays and is used in small portable X-ray ma