Assertion: tourmaline | /r/HasAspect | ionic bond structure
Facets:
value: with the center of ion molecules
type: OTHER
Source sentences:
text: The most important feature of tourmaline does not lie in piezoelectricity or pyroelectricity, but in the fact that tourmaline has an ionic bond structure with the center of ion molecules being fixed in a position off the position where it should be, resulting in a polar crystal which has permanent poles such that a particle thereof, however small it may be, remains polarized on opposite ends thereof, just like permanent poles of a permanent magnet.