Assertion: emerald | /r/HasProperty | a mineral rock
Facets:
Source sentences:
text: An emerald is a mineral rock and a variety of beryl.
text: Emerald (beryl - beryllium aluminum silicate), ruby (corundum - aluminum oxide), sapphire (corundum), opal (silica) and diamond (carbon) are all minerals and have been highly valued by people over the ages because of their rarity and their beauty.
text: An emerald is a mineral rock and a variety of beryl.