Assertion: garnet's discovery | /r/HasProperty | documented in letter
Facets:
value: on june
type: TEMPORAL
value: to the royal society
type: OTHER
Source sentences:
text: He named iridium after Iris (Ἶρις), the Greek winged goddess of the rainbow and the messenger of the Olympian gods, because many of the salts he obtained were strongly colored.[note 2] Discovery of the new elements was documented in a letter to the Royal Society on June 21, 1804.