Assertion: sponge's spicule | /r/HasProperty | calcium carbonate
Facets:
value: in crystalline forms
type: OTHER
value: chiefly
type: DEGREE
Source sentences:
text: Calcareous spicules, characteristic of the Calcarea, are composed chiefly of calcium carbonate in crystalline forms; e.g., calcite, aragonite.
text: Most sponges are too rough for general use due to their structural spicules composed of calcium carbonate or silica.
text: Sponges in this class are typified by skeletal spicules composed of calcium carbonate.