Assertion: copper tourmaline | /r/HasProperty | discovered in nigeria
Facets:
value: since 2001
type: TEMPORAL
value: more recently
type: TEMPORAL
Source sentences:
text: Since 2001 some copper coloured tourmalines have been discovered in Nigeria and slightly more recently in Mozambique but these are generally not as vivid as their Latin American counterparts, despite some colour overlap, and a trained gemmologist with proper equipment can definitively separate the two origins by detecting the lead content that is only found in the African stones.