Related Clues:

• See 9-Down
• Metal containers
• They may be picked out
• Miner's quarry
• Assayers' stuff
• Malachite and others
• They come out at the seams
• Vein materials
• They may be refined
• Raw materials
• They could use some refinement
• Groundbreaking discoveries?
• Rock groups?
• They're in veins
• Miner concerns