Assertion: silica | /r/HasProperty | quartz
Facets:
value: naturally
type: MANNER
Source sentences:
text: Silica can be a naturally occurring substance, like quartz, or it can result from human activities.
text: The process I need to sample involves silica (quartz, fused silica, diatomaceous earth, etc.) that reaches a temperature of only 1100 degrees C  too low for the formation of cristobalite.