Related Clues:

• 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
• Groundbreaking discoveries?
• Zoomed
• Hematite, for one
• Rock groups?