Assertion: tourmaline's color | /r/HasProperty | visible
Facets:
value: at first sight to diamond experts
type: OTHER
value: by transmitted light
type: CAUSE
Source sentences:
text: They may be very pale or so dark that the color is visible by transmitted light only.
text: The color of Argyle diamonds is so unique and discernible at first sight to diamond experts that the pink diamonds of that mine have earned their name in the diamond industry under the term Argyle Diamond.
text: Many of the tourmalines have two colors – one visible on the daily and the other – on artificial light.