Related Clues:

• They're dug for
• Bank deposits, maybe
• Mined finds
• Galena and cinnabar
• They're unrefined
• Sources of nickel, e.g.
• Mining samples
• Bauxite and taconite
• Miner discoveries
• Leadville find
• Geological levels
• Finds in bonanzas
• Mined things
• Arsenopyrite and feldspar
• Bauxite, etc.