Final answer:
Nicholas likely saw the treasure his father was seeking as different from conventional treasures; it turned out to be a mountain made of diamond, and eventually, the mine was sealed to protect the secret and ensure lasting wealth.
Step-by-step explanation:
In “Nicholas's Diary: April 2 and 3,” Nicholas likely perceives the treasure that his father is hunting for as it's not the kind of treasure he expected it to be. Rather than being a traditional trove of gold and silver that one might expect, the treasure turns out to be something much more unexpected and extraordinary. The discovery and secretive harvesting of an entire mountain made of diamond fundamentally changes the notion of what constitutes a treasure. Furthermore, once the wealth from the mine was deemed sufficient, the decision to seal up the mine reflects a deviation from the relentless pursuit typically associated with treasure hunting. Instead, Nicholas's father demonstrates a strategic restraint to ensure the long-term security and exclusivity of his find.