Related Clues:

• Assayers' stuff
• Tram filler
• Malachite and others
• It's fine for a refinery
• They come out at the seams
• Vein materials
• Pay dirt
• They may be refined
• Miner's quest
• Lead ___
• Raw materials
• They could use some refinement
• Bauxite, e.g.
• Subject of testing
• They're in vein