Assertion: carbon pencil | /r/MadeOf | lampblack
Facets:
Source sentences:
text: Carbon pencils are made from lampblack (derived from burning oil), delivering a smooth, dark black line.
text: Carbon pencils are made with lampblack (oil soot) which is a very black form of carbon.
text: Carbon pencils are made from lampblack (derived from burning oil), delivering a smooth, dark black line.