Assertion: emerald's color | /r/CreatedBy | chromium impurities
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Emeralds that were treated to mask internal Besides for Emerald, the mineral Beryl also has other important gem varieties, including blue Aquamarine , pink Morganite , and yellow Heliodor Golden Beryl Pure Beryl is white; the green color of Emerald is usually caused by chromium impurities , and occasionally by vanadium impurities.