Assertion: tourmaline's copper | /r/HasProperty | cu
Facets:
Source sentences:
text: Paraiba-type tourmalines belong to the elbaite species, but contain manganese (Mn) and copper (Cu) with a Cu content of up to 2.30 wt% CuO, as well as bismuth (Bi).
text: A paraíba tourmaline is a blue (electric blue, neon blue, violet blue), bluish green to greenish blue or green elbaite tourmaline, of medium to high saturation and tone, mainly due to the presence of copper (Cu) and manganese (Mn) of whatever geographical origin.