Assertion: diatom's shell | /r/MadeOf | silica
Facets:
Source sentences:
text: The shells (made of silica) cannot decay, and therefore collect together at the bottom of the lake.
text: Algal shells made of silicon are slightly negatively charged.
text: Radiolarians have shells made of silica instead of calcium carbonate.
text: Unlike most algae, though, they have a solid shells made of silica.
text: Diatoms are aquatic algae with transparent shells made of silica.
text: they have hard outer shells made of silicon and oxygen, the same elements that make up glass," Balasubramanian said.