Assertion: sponge's spicule | /r/HasProperty | calcareous
Facets:
Source sentences:
text: The spicules may be calcareous (made mostly of calcium carbonate) or siliceous (chiefly silicic acid).
text: Bath sponges are made of calcereous or siliceous spicules, and they are therefore soft to the touch.
text: Spicules are calcareous (consisting of Calcium Carbonate or Calcite; these spicules occur in the class Calcarea of phylum Porifera) or siliceous (consisting of colloidal Silica or Silicon; these spicules occur in the class Hexactinellida of phylum Porifera) in nature.
text: Spicules are either calcereous (precipitated from calcium ions and carbonate ions) or siliceous (precipitated from silicate salts).