Assertion: tourmaline | /r/HasProperty | heated
Facets:
value: to lighten its color
type: PURPOSE
value: on occasion
type: TEMPORAL
Source sentences:
text: Tourmaline can produce its own electrical charge when put under great pressure and also if it is heated and cooled to extremes.
text: On occasion Tourmaline may be heat treated to lighten its color; for example, a dark green Tourmaline may be heat treated to create an emerald color.
text: Tourmaline does in fact have a pyroelectric quality, meaning that when it is heated it gains a static charge which attracts small particles of dust, paper, lint etc.