Assertion: graphite | /r/HasProperty | a form of lead
Facets:
value: until 1779
type: TEMPORAL
value: for a long time
type: TEMPORAL
Source sentences:
text: Another reason we call it lead is that when graphite was discovered in Cumbria, England during the 1500s, people thought that graphite was a form of lead.
text: lead’ is that graphite was thought to be a type of lead until 1779 when a Swedish chemist discovered it was a mineral form of carbon.
text: Graphite was thought to be a form of lead until 1779, when K.W. Scheele, a Swedish chemist, discovered that the so-called lead used in pencils, was in fact a mineral form of carbon.
text: The pencil core is actually called the “lead” because for a long time, graphite was thought to be a type of lead.