Assertion: lens's quality | /r/HasProperty | poor
Facets:
value: very
type: DEGREE
Source sentences:
text: Early lenses were sometimes made from crystals; one of the oldest known, the Nimrud lens in the British Museum in London, is a piece of quartz (sometimes called "rock crystal") estimated to be 3000 years old and believed to have been used as a magnifying or burning glass, though its optical quality was very poor.