Assertion: agate | /r/HasAspect | a hardness of 7
Facets:
Source sentences:
text: Composed of silicon dioxide (SiO2), it has a hardness of 7, a glassy luster, a conchoidal fracture, and a specific gravity of 2.60.
text: Composed of silicon dioxide (SiO2), it has a hardness of 7, a glassy luster, a conchoidal fracture, and a specific gravity of 2.60.