Assertion: boulder opal | /r/HasProperty | soft
Facets:
value: relatively
type: DEGREE
value: at 6 in hardness
type: OTHER
value: for a gem
type: PURPOSE
Source sentences:
text: At 5.5 to 6 in hardness Boulder Opals are relatively soft for a gem but the hard ironstone backing make them durable enough to survive the odd bump or knock on a hard surface however you should always take care to avoid such abuse.