What was the first source of wealth that the conquistadors exploited for the Spanish crown?

The first source of wealth that the conquistadors exploited for the Spanish crown was gold and silver, particularly from the vast empires in the Americas, such as the Aztec and Inca civilizations. The conquistadors sought precious metals to enrich themselves and the Spanish monarchy, leading to the extraction of vast quantities of gold and silver, especially from mines like Potosí in present-day Bolivia. This wealth significantly boosted Spain's economy and global influence during the 16th century.