Read the passage. Lines 1-6: 1 Truth ran under the rumor like a mineral vein. 2 The surface glittered with easier stones. 3 Men filled their pockets and went away satisfied. 4 Only the patient listened for the deeper strike of the pick. 5 When one hard blue shard came free, it darkened every false jewel. 6 The mine grew quiet. Which interpretation best explains the extended metaphor?