Assertion: engagement ring's diamond | /r/HasProperty | the hardest material
Facets:
value: on earth
type: LOCATION
Source sentences:
text: Beyond their radiance and romantic symbolism, they remain a popular engagement ring stone for more practical reasons: Diamond is the hardest material on Earth, ranking a 10 on the Mohs hardness scale.
text: Diamonds and sapphires are also the hardest gemstones (Diamonds rank 10 and sapphires rank 9 on a 1-10 mineral grading scale called the Mohs scale of hardness) meaning that they’ll hold up well to the everyday wear required of engagement rings.