Assertion: tourmaline | /r/HasProperty | name
Facets:
Source sentences:
text: Tourmaline is a name applied to a family of related minerals, all having essentially the same crystal structure but varying widely in chemical composition, color, and properties.
text: Tourmaline is the name given boron silicate crystals that may bear a variety of elements; Barbosa’s Paraíba is a cupriferous (iron-bearing) variety.