Glittering and mysterious mines give you gold nuggets; after you collect enough, you’ll be able to convert them to gold. In addition, they give you mysterious ore that you can refine for more ore on top of the regular ore you’ll get.

• To extract resources from the Mysterious Mines, your noble should possess the Automation IV talent. Meanwhile, for the Glittering Mines, your noble needs the Improved Automation IV talent. 
• The Collier only has access to Automations IV, while the Prospector has access to the Improved Automations IV talent.