Assertion: magnesium sulfate's sulfur | /r/HasProperty | extracted
Facets:
value: from salt domes
type: LOCATION
value: from pyrite
type: OTHER
Source sentences:
text: By the 3rd century, the Chinese discovered that sulfur could be extracted from pyrite.
text: Elemental sulfur was extracted from salt domes (in which it sometimes occurs in nearly pure form) until the late 20th century.