Assertion: cuttlefish's shell | /r/AtLocation | birdcage
Facets:
value: as a source of calcium
type: PURPOSE
value: often
type: TEMPORAL
value: for beak-sharpening
type: PURPOSE
Source sentences:
text: Ink from the cuttlefish has been used for centuries for writing, and its hard internal shell, the cuttlebone, often is placed in birdcages for beak-sharpening and as a source of calcium.