Assertion: tourmaline | /r/HasAspect | specific gravity
Facets:
Source sentences:
text: Tourmaline has a specific gravity of from 3.1 to 3.2, and a hardness of 7.0 to 7.5 in Mohs' scale of hardness, which is slightly harder than quartz but is a little soft as a jewel.
text: Tourmaline has a specific gravity of from 3.1 to 3.2, and a hardness of 7.0 to 7.5 in Mohs' scale of hardness, which is slightly harder than quartz but is a little soft as a jewel.
text: Tourmaline has a specific gravity ranging from 3.1 to 3.2, and a Mohs hardness ranging from 7.0 to 7.5, indicating that tourmaline is slightly harder than quartz but soft for gems.
text: Tourmaline has a specific gravity of from 3.1 to 3.2, and a hardness of 7.0 to 7.5 in Mohs' scale of hardness, which is slightly harder than quartz but is a little soft as a jewel.