Assertion: alloy's metal | /r/HasProperty | impure
Facets:
value: conversely
type: MANNER
value: often
type: TEMPORAL
Source sentences:
text: An alloy is technically an impure metal, but when referring to alloys, the term impurities usually denotes undesirable elements.
text: Conversely, otherwise pure-metals that simply contain unwanted impurities are often called "impure metals" and are not usually referred to as alloys.