Assertion: alumina | /r/ObjectUse | used as abrasive
Facets:
value: widely
type: DEGREE
Source sentences:
text: Being a very hard material (Mohs hardness 9), alumina is widely used as an abrasive; being extraordinarily chemically inert, it is useful in highly reactive environments such as high pressure sodium lamps.
text: Another 10% produces alumina which is used in chemical, abrasive, and refractory products.
text: It is widely used as an abrasive, including as a much less expensive substitute for industrial diamond.