Assertion: green tourmaline | /r/PartOf | trigonal crystal system
Facets:
Source sentences:
text: Green Tourmaline belongs to the trigonal crystal system and occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section.
text: Green Tourmaline belongs to the trigonal crystal system and occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section.